The Acid Ape Chess User Manual
Acid Ape Studios
2019-11-28

Table of contents

Preface

This manual documents Acid Ape Chess Grandmaster Edition 1.4.2.

This manual is worth reading for users who want to leverage the full potential of Acid Ape Chess Grandmaster Edition.

About the authors

Acid Ape Studios produces:

1 Introduction

Welcome to Acid Ape Chess, the multi-purpose chess suite aimed at the serious player.

Acid Ape Chess is organized with a tools philosophy in mind. You can leverage its modular design to perform common and less common chess-related tasks.

Acid Ape Chess focuses on:

The following chapters describe Acid Ape Chess in details and provide examples and step-by-step tutorials.

2 App structure

Acid Ape Chess is organized into pages. Upon startup, the New Game page is displayed.

The Acid Ape Chess screen is composed of:

2.1 The title bar

The title bar
FIGURE 2.1: The title bar

The title bar contains:

2.1.1 The pager

The pager
FIGURE 2.2: The pager

Pressing the title bar toggles the pager.

The pager displays realtime miniatures of pages.

To close a page, swipe it out to the left or right screen edge.

To reset to the startup state (closing all pages and opening the New Game page), press the trashcan button (at the bottom right of the screen).

2.1.2 The attention icon

If a page signals for attention, the icon of that page is displayed at the left of the navigation buttons.

Pressing the attention icon navigates to the signaling page and clears the icon.

Examples:

  • a game page signals for attention if a move has been played;
  • a chat page signals for attention if a message has been received.

2.1.3 The page navigation buttons

At the right of the title bar, back/forward buttons allow to navigate through the page history list.

2.2 The toolbar

The toolbar
FIGURE 2.3: The toolbar

The toolbar contains the main menu button and page-specific buttons.

3 Pages

Pages can be switched by:

To close a page:

Acid Ape Chess exits when the last remaining page is closed.

Notable Acid Ape Chess pages include:

3.1 The board theme page

The board theme page
FIGURE 3.1: The board theme page

The board theme page allows you to choose from a list of predefined chessboard themes and piece sets, and to toggle coordinates display.

3.1.1 Accessing the page

The board theme page can be accessed by pressing the Theme button in the Board section of the settings page.

3.2 The chat page

The chat page
FIGURE 3.2: The chat page

The chat page allows you to chat with other FICS and ICC users.

3.2.1 Accessing the page

The chat page can be accessed by using Online / OTB > Chat in the main menu.

3.2.2 Usage

The chat page contains one tab per FICS/ICC chess account.

A number of standard chat channels are supported by Acid Ape Chess.

Acid Ape Chess sends chat messages using the tell FICS/ICC command.

3.2.3 Supported channels

3.2.3.1 FICS

Channel Description
#1 Server help.
#4 Guest help.
#50 Registered chat.
#53 Guest chat.
TABLE 3.1: Supported FICS channels

3.2.3.2 ICC

Channel Description
#1 Server help.
#250 Lobby.
TABLE 3.2: Supported ICC channels

3.3 The console page

The console page
FIGURE 3.3: The console page

The console page allows you to use the FICS and ICC consoles.

3.3.1 Accessing the page

The console page can be accessed by using Online / OTB > Console in the main menu.

3.3.2 Usage

The console page contains one tab per FICS/ICC chess account.

To display the server help, type help.

3.4 The engine manager page

The engine manager page
FIGURE 3.4: The engine manager page

The engine manager page allows you to add, remove or configure chess engines.

While similar functionalities are provided by the ENGINE and SIMUL tabs of the New Game page, this page might be more convenient if you have added a large number of engines.

3.4.1 Accessing the page

The engine manager page can be accessed by using Settings and help > Engines in the main menu.

3.5 The game page

The game page
FIGURE 3.5: The game page

The game page allows you to play, view, analyze and edit a game.

3.5.1 Accessing the page

The game page can be accessed via various parts of the app.

Most notably, from the main menu:

  • an online game, engine game or simul can be created with Game > New;
  • a PGN file can be opened with Game > Explorer;
  • a scratch board can be created with Position > New;
  • a custom game (two-player game, engine duel, asymmetric clocks, custom position, ...) can be created with Position > Play;
  • a live online game can be watched with Online / OTB > Games;
  • a live OTB game can be watched with Online / OTB > Relayed games;
  • a recorded OTB game can be opened via Online / OTB > Players.

3.5.2 Inter page communication

In the context of inter page communication, the game page is both a game data source and a game data sink.

3.5.3 The chessboard

The chessboard
FIGURE 3.6: The chessboard

The chessboard is obviously the central feature of Acid Ape Chess.

You can input moves using two different methods:

  • press the source square, then the destination square;
  • drag the piece from the source square to the destination square.

The board appearance can be modified in the board theme page.

3.5.3.1 Highlighted squares

Specific chessboard squares may be hilighted.

3.5.3.1.1 Moves
Square Description
The move source square The source of the current move.
The touch feedback square The square being touched.
The illegal square The square being touched is an illegal source or destination.
TABLE 3.3: Move highlighters
3.5.3.1.2 OTB play
Square Description
The DGT move in progress square The square participates in an uncompleted OTB move. Complete your move.
The DGT error square The piece on the physical board square differs from the piece on the Acid Ape Chess board square. Fix the physical square.
TABLE 3.4: OTB play highlighters
3.5.3.1.3 Miscellaneous
Square Description
The puzzle hint move source square The source of the current puzzle hint.
TABLE 3.5: Miscellaneous highlighters

3.5.3.2 Move arrows

Arrows may appear over the chessboard to highlight specific moves.

3.5.3.2.1 Game flow

These arrows are displayed when made relevant by the current move list location.

Arrow Description
The last move arrow The last move.
The mainline arrow The next move in the current line.
The variation arrow The start of a variation.
TABLE 3.6: Game flow arrows
Note
These arrows can be toggled in the settings page.
3.5.3.2.2 Engine computations

These arrows are displayed when a chess engine is playing the game.

Arrow Description
The best move arrow The best move.
The ponder move arrow The probable next opponent move.
The best reply arrow The best reply to the next opponent move.
TABLE 3.7: Engine computations arrows
Note
In a human vs engine game, these arrows are only displayed if the engine information subpage is currently active. In an engine duel, these arrows are always displayed.
3.5.3.2.3 Analysis

These arrows are displayed when analysis is enabled.

Arrow Description
The forced move arrow The only legal move.
The engine #1 arrow The evaluation of engine 1.
The engine #2 arrow The evaluation of engine 2.
The engine #3 arrow The evaluation of engine 3.
The engine #4 arrow The evaluation of engine 4.
The engine #5 arrow The evaluation of engine 5.
The engine #6 arrow The evaluation of engine 6.
The engine #7 arrow The evaluation of engine 7.
The engine #8 arrow The evaluation of engine 8.
TABLE 3.8: Analysis arrows
3.5.3.2.4 Endgame tablebases

These arrows are displayed when analysis is enabled and when the endgame tablebases online service could be queried (the board must not contain more than 7 pieces).

Arrow Description
The tablebase win arrow The path to the EGTB win.
The tablebase cursed win arrow The path to the EGTB cursed win.
The tablebase draw arrow The path to the EGTB draw.
The tablebase blessed loss arrow The path to the EGTB blessed loss.
The tablebase loss arrow The path to the EGTB loss.
TABLE 3.9: Endgame tablebases arrows

Cursed wins and blessed losses are mates that can be forced, but not under the fifty-move rule.

3.5.3.2.5 OTB play
Arrow Description
The pending clock move arrow A legal move not yet confirmed by a clock tap.
TABLE 3.10: OTB play arrows
3.5.3.2.6 Miscellaneous
Arrow Description
The premove arrow The current premove, and the move currently being pressed in the opening explorer.
The puzzle hint arrow The puzzle hint.
TABLE 3.11: Miscellaneous arrows
3.5.3.2.7 Score gauges

Chess engine evaluation arrows feature a score gauge.

Note
The numeric score is displayed in the corresponding engine information subpage.
3.5.3.2.7.1 Relative score

When the Display relative eval option is enabled in the settings page, the score gauge is relative to the side to move and ranges from 0 to 100 centipawns.

Arrow Description
The -1.0 arrow The side to move is losing by 100 centipawns or more.
The -0.5 arrow The side to move is losing by 50 centipawns.
The 0.0 arrow The score is absent, zero or neglectable.
The +0.5 arrow The side to move is winning by 50 centipawns.
The +1.0 arrow The side to move is winning by 100 centipawns or more.
TABLE 3.12: Relative score gauge examples
3.5.3.2.7.2 Absolute score

When the Display relative eval option is disabled in the settings page, the score gauge is relative to white, ranges from -100 to 100 centipawns and is centered at 0.

Arrow Description
The -1.0 arrow Black is winning by 100 centipawns or more.
The -0.5 arrow Black is winning by 50 centipawns.
The 0.0 arrow Sides are equal.
The +0.5 arrow White is winning by 50 centipawns.
The +1.0 arrow White is winning by 100 centipawns or more.
TABLE 3.13: Absolute score gauge examples

3.5.3.3 The eval gauge

The eval gauge displaying a +0.25 eval
FIGURE 3.7: The eval gauge displaying a +0.25 eval

The eval gauge displays chess engine and EGTB evaluations.

The displayed value is expressed in pawn units and clamped to the range [-4.0, +4.0].

Note
For clarity purposes, the eval gauge ignores the Display relative eval setting: it always displays absolute evaluations.
3.5.3.3.1 Operation

The eval gauge automatically appears in specific contexts. They are listed in order of precedence.

3.5.3.3.1.1 During analysis

If analysis is in progress, the eval gauge displays the following data:

  • if an EGTB result is available, that result;
  • otherwise, if one of the analyzers has computed a mate, that mate;
  • otherwise, the average eval of the participating analyzers.
3.5.3.3.1.2 During a human vs engine game

If a human vs engine game is in progress, the eval gauge is displayed only if you show the engine information subpage, and displays the following data:

  • if the engine has computed a mate, that mate;
  • otherwise, the engine evaluation.
3.5.3.3.1.3 During an engine duel

If an engine duel is in progress, the eval gauge is displayed only if you show at least one of the two engine information subpages, and displays the following data:

  • if one of the visible engine subpages has computed a mate, that mate;
  • otherwise, the average eval of the visible engine subpages.

This means that you can tie the eval gauge to a specific engine by displaying only that subpage.

3.5.3.3.1.4 If auto annotations are present

If the current move has an auto annotation, the eval gauge displays the engine evaluation of the annotation.

3.5.4 The subpage area

The subpage area
FIGURE 3.8: The subpage area

The subpage area contains a number of utility subpages (which may or may not be present depending on the game context).

At the top left of the subpage area, subpage management buttons can be used to alter the layout of the area.

Button Description
The subpage add button Split the subpage area vertically.
The subpage close button Unsplit the subpage area.
The subpage maximize button Maximize the subpage.
The subpage maximize button Unmaximize the subpage.
The subpage swap button Swap the top and bottom subpages.
TABLE 3.14: Subpage management buttons

You can move between subpages by swiping a subpage left or right, or by pressing a subpage icon at the right of the subpage title.

Pressing the subpage title toggles the subpage selector. Long-pressing the subpage title displays the subpages layout selection dialog.

Some subpages cannot be closed, while some others can usually be closed by pressing the toggle button that opened them. Consult the relevant subpage section for details.

3.5.4.1 Major subpages

3.5.4.1.1 Game information
The game information subpage
FIGURE 3.9: The game information subpage

This subpage provides informations about the current game.

3.5.4.1.1.1 Subpage presence

This subpage appears automatically when relevant and cannot be closed.

3.5.4.1.1.2 Features

The game information subpage displays informations and statistics about the current game.

If a player name is underlined, pressing it opens the OTB player information page or the user information page (depending on the player type).

The game information subpage is also the subpage from where you can enable the fullscreen clock. When relevant, a FULLSCREEN CLOCK button appears at the bottom of the subpage (on smaller screens, you might have to scroll the subpage down a bit to reach that button).

3.5.4.1.2 The move list
The move list
FIGURE 3.10: The move list

This subpage allows you to view or edit the move list.

3.5.4.1.2.1 Subpage presence

This subpage appears automatically when relevant and cannot be closed.

3.5.4.1.2.2 Features
  • Variations;
  • ECO display;
  • Move annotations;
  • Comments.
3.5.4.1.2.3 Action buttons

Action buttons are present at the right of the move list.

Button Description
The enable edition button Enable edition mode.
The disable edition button Disable edition mode.
The recognize move button Enter a move via speech recognition.
TABLE 3.15: Action buttons
3.5.4.1.2.4 Edition mode

When edition mode is enabled, the move list can be edited by navigating to the appropriate node, then pressing a button in the edition toolbar.

Note
Changes are applied to the backing file when the game is saved.
3.5.4.1.2.4.1 The edition toolbar
Button Description
The truncate line button Truncate the current line.
The move variation up button Move the current variation up.
The move variation down button Move the current variation down.
The edit annotation button Edit the annotation of the current move.
The add comment before button Add a comment before the current node.
The add comment after button Add a comment after the current node.
The edit comment button Edit the current comment.
The delete comment button Delete the current comment.
TABLE 3.16: Edition toolbar buttons
3.5.4.1.3 The digital clock
The digital clock with all segments on
FIGURE 3.11: The digital clock with all segments on

This subpage provides a visually appealing digital clock, loosely modeled after the well-known DGT3000.

3.5.4.1.3.1 Subpage presence

This subpage appears automatically when relevant and cannot be closed.

3.5.4.1.3.2 Clock buttons

The clock buttons can be used to toggle the clock beeper and autoflagging. The state of these options is app-global, persisted, and displayed at the left of the clock LCD.

Button Description
The sound button Toggle the clock beeper.
The flag button Toggle autoflagging.
TABLE 3.17: Clock buttons

When the clock beeper is enabled, a player is alerted that he is running out of time with:

  • short beeps when 10, 5, 4, 3 and 2 seconds remain;
  • a continuous beep during the last second.
Note
The sound button only toggles the clock beeper, not other app sounds such as clock taps. The master app sound toggle is in the settings page. For the clock beeper to emit sounds, both toggles must be on.

If autoflagging is enabled, the opponent is automatically flagged when he runs out of time. If a player is already out of time when autoflagging is enabled, that player is flagged immediately.

3.5.4.1.3.3 LCD symbols
Symbol Description
The period LCD symbol This side's time control has multiple periods. The current period number is indicated.
The sound LCD symbol The clock beeper is enabled.
The flag LCD button Autoflagging is enabled.
The large flag LCD button This side has run out of time (blinking).
The pawn LCD button This side is to move.
The Fisch LCD button This side uses an increment.
TABLE 3.18: LCD symbols
3.5.4.1.4 Engine information
The engine information subpage
FIGURE 3.12: The engine information subpage

This subpage displays the output of a chess engine.

3.5.4.1.4.1 Subpage presence

One instance of this subpage is automatically added for each engine running in the parent game page, and is automatically removed when the engine is terminated.

3.5.4.1.4.2 Output format

This subpage includes the following items:

  • one or more colored squares displaying the colors of the engine computations arrows;
  • if an endgame tablebases match is found, a colored square displaying the color of the EGTB arrow;
  • the time spent searching the current position;
  • a statistics header;
  • the principal variation.
3.5.4.1.4.2.1 Statistics

The statistics header may contain the following fields:

Field Description
score The engine evaluation score in pawns.
mate If a forced mate is found, the number of moves leading to it.
depth The search tree depth.
nodes The number of nodes evaluated.
n/s The engine throughput in nodes per second.
TABLE 3.19: Statistics fields
Note
By default, the engine evaluation score and mate move count are relative to the side to move (positive when the side to move is winning, zero if equal, negative when the side to move is losing). Absolute score and mate move count display (positive when white is winning, zero when equal, negative when black is winning) can be selected by disabling the Display relative eval option in the settings page.
3.5.4.1.4.3 Analysis buttons

Analysis buttons are displayed when the engine is participating in analysis (not when the engine is playing a game).

3.5.4.1.4.3.1 Global analysis buttons

Global analysis buttons are present at the right of the subpage. They operate the global analysis controller associated with the containing game page.

Button Description
The add analyzer button Add an analyzer.
The remove analyzer button Remove an analyzer.
TABLE 3.20: Global analysis buttons
3.5.4.1.4.3.2 Engine analysis buttons

Engine analysis buttons are present over the bottom left of the subpage. They operate the analysis controller associated with the current engine.

Button Description
The play move button Play the engine best move.
The start auto analysis button Start auto analysis.
The stop auto analysis button Stop auto analysis.
TABLE 3.21: Engine analysis buttons
3.5.4.1.5 Analysis information
The analysis information subpage
FIGURE 3.13: The analysis information subpage

This subpage displays a summary of each analyzer (a chess engine or the endgame tablebases).

To toggle analysis, use the analysis toolbar button of the game page.

3.5.4.1.5.1 Subpage presence

This subpage is present if you have enabled it.

3.5.4.1.5.2 Output format

Each engine analyzer entry includes the following items:

  • the engine name;
  • the engine throughput in kilonodes per seconds;
  • the engine evaluation score in pawns, or if a forced mate is found, the number of moves leading to it;
  • the engine best move;
  • a close button for removing the analyzer.

Pressing an engine name splits the subpage area vertically and displays the engine information subpage in the other pane.

Note
By default, the engine evaluation score and mate move count are relative to the side to move (positive when the side to move is winning, zero if equal, negative when the side to move is losing). Absolute score and mate move count display (positive when white is winning, zero when equal, negative when black is winning) can be selected by disabling the Display relative eval option in the settings page.

The EGTB entry only appears if an EGTB match is found, and includes the following items:

  • the game result (win, cursed win, draw, blessed loss or loss);
  • the best move;
  • the distance to zero ply (the next pawn move or capture).

Cursed wins and blessed losses are mates that can be forced, but not under the fifty-move rule.

3.5.4.1.5.3 Action buttons

Action buttons are present at the right of the subpage.

Button Description
The add analyzer button Add an analyzer.
TABLE 3.22: Action buttons
Note
The endgame tablebases analyzer is always enabled and cannot be added with the add button.
3.5.4.1.6 The opening explorer
The opening explorer
FIGURE 3.14: The opening explorer

This subpage displays the opening moves, players and games related to the current position.

To toggle this subpage, use the opening explorer toolbar button of the game page.

3.5.4.1.6.1 Subpage presence

This subpage is present if you have enabled it.

3.5.4.1.6.2 Data source

The opening explorer retrieves its data online from the large Acid Ape Chess game database.

3.5.4.1.6.3 Tabs

Tabs can be switched using the buttons at the right of the subpage.

3.5.4.1.6.3.1 The moves tab
The moves tab
FIGURE 3.15: The moves tab

The moves tab lists the 20 most played moves at the current position.

For each move, the following information is provided:

  • the move;
  • the number of games in which it was played;
  • a bar chart displaying the percentage of these games that ended in a white win (white background), draw (gray background) and black win (black background).

Moves are sorted by game count in descending order.

Pressing a move entry plays that move.

Keeping the move entry pressed highlights the move with an arrow.

3.5.4.1.6.3.2 The players tab
The players tab
FIGURE 3.16: The players tab

The players tab lists the 20 players that encountered the current position the most (as the side that just moved, or as white if the current position is the initial position).

For each player, the following information is provided:

  • his picture, if available;
  • his chess title;
  • his name;
  • his most recent ELO rating in the database;
  • his chess federation;
  • a summary of the most recent game in which he encountered the current position;
  • the number of games in which he encountered the current position.

Pressing a player entry opens the player information page for that player.

3.5.4.1.6.3.3 The games tab
The games tab
FIGURE 3.17: The games tab

The games tab lists the 20 most recent games in which the current position was encountered.

Pressing a game entry opens the game in a new game page and navigates to the current position.

3.5.4.1.7 Chat
Chat
FIGURE 3.18: Chat

This subpage allows you to chat with your opponent (using the chat facilities of the chess server the game is played on).

3.5.4.1.7.1 Subpage presence

This subpage appears automatically when relevant and cannot be closed.

3.5.4.1.7.2 Action buttons

Action buttons are present at the right of the subpage.

Button Description
The keyboard button Send a message.
The block button Block your opponent.
TABLE 3.23: Action buttons
3.5.4.1.7.3 Sending a message to the opponent
  1. Switch to the chat subpage.
  2. Press the keyboard button.
  3. Type your message and confirm.

3.5.4.2 Choosing a promotion piece

The promotion piece selector
FIGURE 3.19: The promotion piece selector

When a promotable pawn is selected, a promotion piece selector appears in the bottom left corner of the subpage area.

Select the piece to promote the pawn to, then play the promotion move.

3.5.5 The move list navigation buttons

The move list navigation buttons
FIGURE 3.20: The move list navigation buttons

You can navigate in the move list by using the navigation buttons in the bottom right corner of the screen. Keep a button pressed for faster navigation.

3.5.6 The toolbar

Toolbar buttons are described below. Note that some of these buttons are only available in a given context (for instance only if the game is in progress, or only for engine games).

Button Description
The flip toolbar button Flip the board.
The resign toolbar button Resign the game.
The draw toolbar button Offer or claim a draw.
The draw armed toolbar button Claim a draw after next move.
The takeback toolbar button Request a takeback.
The resume toolbar button Start or resume the game.
The pause toolbar button Pause the game.
The rematch toolbar button Offer a rematch.
The start analysis toolbar button Start analysis.
The stop analysis toolbar button Stop analysis.
The enable opening explorer toolbar button Enable the opening explorer.
The enable opening explorer toolbar button Disable the opening explorer.
The auto annotate toolbar button Open the auto annotate dialog.
TABLE 3.24: Toolbar buttons

3.6 The games page

The games page
FIGURE 3.21: The games page

The games page lists the games currently in progress on FICS and ICC.

Press a game to observe it.

3.6.1 Accessing the page

The games page can be accessed by using Online / OTB > Games in the main menu.

3.6.2 The toolbar

Button Description
The refresh toolbar button Refresh the game list.
TABLE 3.25: Toolbar buttons

3.7 The manual page

The manual page
FIGURE 3.22: The manual page

The manual page allows you to browse the Acid Ape Chess User Manual.

3.7.1 Accessing the page

The manual page can be accessed by using Settings and help > Help in the main menu.

3.7.2 The breadcrumb

Scroll the breadcrumb and press one of its components to navigate to the corresponding manual section.

3.7.3 The toolbar

Button Description
The back toolbar button Go back in the history list.
The forward toolbar button Go forward in the history list.
The mark toolbar button (Normal press) Navigate to the saved mark.
The mark toolbar button (Long press) Save the mark.
TABLE 3.26: Toolbar buttons

3.7.4 The section navigation buttons

You can navigate through manual sections sequentially by using the navigation buttons in the bottom right corner of the screen. Keep a button pressed for faster navigation.

3.8 The New Game page

The New Game page
FIGURE 3.23: The New Game page

The New Game page allows you to quickly play online or against a chess engine.

Note
Other game types (human duel, engine duel) and options (asymmetric clocks, custom position) are available in the play dialog.

3.8.1 Accessing the page

The New Game page is displayed when Acid Ape Chess starts, and can be explicitly accessed by using Game > New in the main menu.

3.8.2 Color and time selection

3.8.2.1 The color selector

The color selector
FIGURE 3.24: The color selector

The color selector allows you to select the user color.

Button Description
The AUTO button Select a random color.
The WHITE button Select white.
The BLACK button Select black.
TABLE 3.27: Color selector buttons

3.8.2.2 The time selector

The time selector
FIGURE 3.25: The time selector

The time selector allows you to choose a time control.

By default, the selector is in custom mode, allowing you to set a specific time and Fischer increment.

Press the settings button to select more advanced time controls from the time control selection dialog.

When a player runs ouf ot time, he usually loses the game (but not always: see autoflagging).

Note
Online chess servers only support a simple single-period time control, with an optional Fischer increment but without a move limit.

3.8.3 Chess960 and Blindfold toggles

Chess960 and Blindfold toggles
FIGURE 3.26: Chess960 and Blindfold toggles

The Chess960 button toggles the Chess960 mode. In this mode, a random Chess960 position is used for the new game.

The blindfold button toggles the blindfold mode. In this mode, the board is masked and moves must be entered via speech recognition.

3.8.4 Game type selection

The game type selector
FIGURE 3.27: The game type selector

The game type selector allows you to choose between different game types.

3.8.4.1 The ONLINE tab

The ONLINE tab
FIGURE 3.28: The ONLINE tab

Select this tab to play a game on an online chess server.

By default, guest accounts for the three supported servers are configured. You can add more accounts (guest or authenticated) with the add toolbar button at the bottom of the screen.

The connection status of an account is displayed at the bottom right of its icon.

Icon Description
Not connected.
Connecting Connecting.
Connected Connected.
Contact lost Contact lost.
TABLE 3.28: Connection status

An opponent ELO range can be selected using the bottom slider. Note that if a Lichess account is selected, this slider is only available if the account is not anonymous.

By default, an unrated game is created. To play a rated game, select an account having an username and password, then press the trophy icon at the left of the PLAY/CANCEL button.

3.8.4.2 The ENGINE tab

The ENGINE tab
FIGURE 3.29: The ENGINE tab

Select this tab to play a game against a chess engine installed on your device.

Acid Ape Chess ships with three builtin engines. You can add more engines with the add toolbar button at the bottom of the screen.

If the selected engine supports adjustable strength, the engine strength can be selected using the bottom slider.

If the selected engine supports personalities, a personality selector is displayed instead of the strength slider. At the time of this writing, one such engine (Rodent III) can be found in our separate Chess Engines Collection package. This package can be quickly installed using the add toolbar button.

Note
The ELO rating at the right of each engine is updated every 24 hours from CCRL 40/40.

3.8.4.3 The SIMUL tab

The SIMUL tab
FIGURE 3.30: The SIMUL tab

Select this tab to play a simul against multiple instances of a chess engine installed on your device.

Differences with the ENGINE tab:

  • the default strength is 50% (it is assumed that you will prefer weaker opponents when playing many of them);
  • a boards control allows you to select the number of opponents.
Warning
The boards value defaults to a small number (smaller than most real life exhibitions) for good reasons. Since one engine instance is running per board, you might exceed your device processor and/or memory capabilities by inadvertently configuring too many boards (if your device becomes overloaded, it might freeze for long periods while trying to recover).

3.8.5 The PLAY/CANCEL button

The PLAY/CANCEL button
FIGURE 3.31: The PLAY/CANCEL button

Press this button to create a game of the selected type or to cancel a seek in progress.

3.9 The OTB player information page

The OTB player information page
FIGURE 3.32: The OTB player information page

The OTB player information page displays the data, statistics and entire official game history of a given OTB player.

Press a game to open it in a new game page.

You can conveniently search for the player on the Internet using the page toolbar.

3.9.1 Accessing the page

The OTB player information page can be accessed via Online / OTB > Players in the main menu.

In some cases, it can also be accessed by clicking the name of a player in the game information subpage.

3.9.2 Data source

The OTB player information page retrieves its data online from the large Acid Ape Chess game database.

3.9.3 Player information

The player information dock
FIGURE 3.33: The player information dock

The player information dock displays the player's title, full name, ELO rating, federation and statistics.

These statistics include the player's official record in the standard +wins =draws -losses form, and are updated when the game list is narrowed down via filtering.

3.9.4 Filtering games

You can filter games by entering search terms in the search box, and/or by using the filter buttons in the page toolbar.

3.9.5 The toolbar

Button Description
The favorite on toolbar button Mark or unmark the player as a favorite.
The opponent sex filter toolbar button Cycle the opponent sex filter.
The color and ECO filter toolbar button Filter the game list by color and/or opening.
The web toolbar button Search for the player on the web.
The Wikipedia button Search for the player on Wikipedia.
TABLE 3.29: Toolbar buttons

3.10 The PGN explorer page

The PGN explorer page
FIGURE 3.34: The PGN explorer page

The PGN explorer page allows you to manipulate and open PGN files stored on your device or on a SD card.

3.10.1 Accessing the page

The PGN explorer page can be accessed by using Game > Explorer in the main menu.

It is also automatically opened by Acid Ape Chess for displaying a multi-game PGN file from your web browser or from an external file manager.

3.10.2 Overview

The PGN explorer functions like a typical mobile file manager, with first-class support for PGN files:

  • a PGN file containing one game or less is displayed as a normal file;
  • a PGN file containing more than one game is displayed as a virtual directory where each game of the PGN file is a virtual file.

This design allows you to navigate inside a PGN file and manipulate individual games as if they were files (delete them from the PGN file, copy them and so on).

3.10.3 The header

The header
FIGURE 3.35: The header

The header contains the Home button, the breadcrumb and the Create button.

3.10.3.1 The Home button

Press the home button to navigate to the home directory: Internal storage/Acid Ape Chess/Games.

This is where your games are autosaved and adjourned.

Long-press the home button to open the home directory in a new page.

3.10.3.2 The breadcrumb

Scroll the breadcrumb and press one of its components to navigate to the corresponding location.

Long-press a component to open that location in a new page.

3.10.3.3 The Create button

Press the create button to create a directory or an empty PGN file.

The file or directory will be created in the current location.

3.10.4 File operations

To operate on a single item (game, file or directory), use its context menu by long-pressing it.

To operate on multiple items, use the Select toolbar button to enable multiple selection mode.

The Select toolbar button
FIGURE 3.36: The Select toolbar button

File operations are achieved with the cut/copy/paste file management semantics you are used to.

3.10.5 Multiple selection mode

By default, the PGN explorer is in single selection mode (pressing an item opens it). Pressing the Select toolbar button enables multiple selection mode. Pressing it again selects all items. And again, clears the selection.

When multiple selection mode is enabled:

  • pressing an item selects or deselects it;
  • the multiple selection toolbar is displayed, allowing you to operate on the selected items.

3.10.5.1 The multiple selection toolbar.

The multiple selection toolbar.
FIGURE 3.37: The multiple selection toolbar.

The multiple selection toolbar contains the following buttons (from left to right):

  • the Open button: open the selected games in new game pages;
  • the Cut button: start a cut operation on the selected items;
  • the Copy button: start a copy operation on the selected items;
  • the Delete button: move the selected items to the trash;
  • the Close button: disable multiple selection mode.

3.10.6 The clipboard

The PGN explorer maintains a clipboard used for file operations.

3.10.6.1 The cut toolbar

When cut items are in the clipboard, a toolbar similar to the following one appears:

The clipboard toolbar for cut items
FIGURE 3.38: The clipboard toolbar for cut items

Pressing the MOVE HERE button effectively launches the move operation. Pressing the Close button cancels the operation.

3.10.6.2 The copy toolbar

When copied items are in the clipboard, a toolbar similar to the following one appears:

The clipboard toolbar for copied items
FIGURE 3.39: The clipboard toolbar for copied items

Pressing the COPY HERE button effectively launches the copy operation. Pressing the Close button cancels the operation.

3.10.7 The trash

The trash is located in Local, the root location. It can be accessed with the breadcrumb.

3.10.8 The toolbar

Button Description
The select toolbar button Enable multiple selection mode.
The change sort order toolbar button Change the sort order.
TABLE 3.30: Toolbar buttons
Note
The sort order is per-location and saved to the Acid Ape Chess settings.

3.11 The physical board page

The physical board page allows you to connect to a physical board and test it.

From this page, you can also:

3.11.1 Accessing the page

The physical board page can be accessed by using Settings and help > e-Board in the main menu.

Note
When the physical board page is opened with no physical board connected, the Bluetooth connectivity of your device is automatically enabled.

3.11.2 Inter page communication

In the context of inter page communication, the physical board page is a game data source.

3.11.3 The physical board list

The physical board list
FIGURE 3.40: The physical board list

When no physical board is connected, the page allows you to scan for Bluetooth physical boards and connect to one.

3.11.3.1 The toolbar

Button Description
The toggle Bluetooth toolbar button Toggle your device's Bluetooth connectivity.
The scan toolbar button Scan for Bluetooth devices.
TABLE 3.31: Toolbar buttons

3.11.4 The physical board information

The physical board information
FIGURE 3.41: The physical board information

When a physical board is connected, the page displays:

  • the state of board;
  • the board properties (as obtained from the board);
  • the state and properties of the physical clock, if one is connected.

3.11.4.1 The toolbar

Button Description
The flip toolbar button Flip the Acid Ape Chess interpretation of the physical board orientation.
The toggle clock at left button Toggle the side of the physical clock relative to the board (left/right).
The settings button Configure the physical board.
The disconnect toolbar button Disconnect from the physical board.
TABLE 3.32: Toolbar buttons

3.11.4.2 The status icons

Icon Description
The clock turn left status icon A physical clock is connected and its lever is up on the left side.
The clock turn right status icon A physical clock is connected and its lever is up on the right side.
The battery status icon The board battery state.
TABLE 3.33: Status icons
Note
When connected to a DGT Smart Board, the position of the DGT3000 turn lever is not updated. However, the lever position is properly detected during a game.

3.12 The player manager page

The player manager page
FIGURE 3.42: The player manager page

The player manager page allows you to add, remove and edit human players that will be interacting with this installation of Acid Ape Chess.

By default, your player entry is automatically added as Myself; your country is autodetected from the language settings of your device.

You can manage players with the page toolbar or the context menu of a player.

3.12.1 Accessing the page

The player manager page can be accessed by pressing MANAGE PLAYERS in the Players section of the settings page.

3.12.2 Uses of human players

3.12.2.1 Lichess guest play

Lichess names all guest players Anonymous. This can be confusing when reviewing saved games, and does not look nice when playing.

In Acid Ape Chess, if your Lichess player is Anonymous, it is replaced by the default player defined in the player manager.

This default player is indicated with a distinguishable star icon, and can be changed by either of the following:

  • selecting a player, then pressing the star icon in the toolbar;
  • long-pressing a player, then pressing Set as default.
Note
Changing Anonymous to the default player is a client-side replacement only. Your Lichess opponent will still see you as Anonymous, even if he is also using Acid Ape Chess.
Note
The default player is not used on FICS and ICC, because these servers allocate a random username to guest players.

3.12.2.2 Engine and simul games

When playing against a chess engine (or multiple engines in the case of a simul), the default player is used as the human side.

3.12.2.3 OTB games

You might have a group of friends, colleagues or relatives with whom you are frequently playing OTB games using Acid Ape Chess connected to a physical board.

Adding a player entry for each group member allows for neat publication-ready data. You can for instance publish PGN files on your company intranet, or share your saved games using the game sharing feature.

It also makes for a nicer fullscreen clock display during the game.

3.13 The players page

The players page
FIGURE 3.43: The players page

The players page lists:

3.13.1 Accessing the page

The players page can be accessed by using Online / OTB > Players in the main menu.

3.13.2 The OTB tab

The OTB tab lists the players of the Acid Ape Chess game database.

The player list can be filtered by name (using the search box), by sex (using the toolbar button) and by ELO (using the slider at the bottom of the tab). The sort order can be changed using the toolbar button.

Pressing a player opens the OTB player information page.

3.13.2.1 The toolbar

Button Description
The toggle favorites toolbar button Toggle between displaying all players or only favorite ones.
The cycle sex toolbar button Cycle the player sex filter.
The change sort order toolbar button Change the sort order.
TABLE 3.34: Toolbar buttons

3.13.3 The FICS, ICC and Lichess tabs

These tabs list the online users currently connected to the respective chess server.

Pressing an user opens the user information page.

Note
The Lichess player list is not very representative, as Lichess servers only list 50 users (seemingly chosen at random). You can however search for specific Lichess players by pressing Search for more in the toolbar of the Lichess tab.

3.14 The position editor page

The position editor page
FIGURE 3.44: The position editor page

The position editor page allows you to edit a chess position and use it for various tasks.

3.14.1 Accessing the page

The position editor page can be accessed by using Position > Edit in the main menu.

3.14.2 Inter page communication

In the context of inter page communication, the position editor page is both a game data source and a game data sink.

3.14.3 Editing the position

3.14.3.1 Adding pieces

Select a piece in the bottom piece picker. This piece becomes the selected source piece.

You can now click on one or more board squares to add the selected source piece to these squares.

If a square is already occupied, it is replaced by the selected source piece.

3.14.3.2 Removing a piece

To remove a piece, first unselect the selected source piece (if any) by pressing it in the bottom piece picker, then:

  1. press the piece to remove;
  2. press the trashcan icon.

3.14.3.3 Editing position properties

To edit the position properties (move number, castle rights, etc), press the properties button in the page toolbar.

To toggle the side to move, press the side to move button in the page toolbar (the side to move is displayed in the page title bar).

3.14.3.4 Position legality

If you edit the position in a way that makes it illegal, a red warning message is displayed at the top of the screen.

3.14.4 Using the position

3.14.4.1 Analyzing the position

Use Position > Analyze in the main menu. This creates a new game page in which position analysis is enabled on the position.

3.14.4.2 Saving the position

Use Game > Save in the main menu. This opens a dialog which allows you to save the position to a PGN file.

3.14.4.3 Copying the FEN string to the clipboard

Use Position > Copy FEN to clipboard in the main menu.

3.14.4.4 Playing a game from the position

Use Position > Play in the main menu. This opens the play dialog, allowing you to create an OTB or engine game from the position.

Note
In Acid Ape Chess, this is how you can assign a chess handicap (for instance pawn odds) to one side. Edit the initial position to match the desired handicap, then create a game out of it.

3.14.5 The toolbar

Button Description
The flip toolbar button Flip the board.
The toggle side to move toolbar button Toggle the side to move.
The properties toolbar button Edit the position properties.
The reset toolbar button Reset to the standard initial position.
The clear toolbar button Remove all pieces from the board.
TABLE 3.35: Toolbar buttons

3.15 The puzzle collection page

The puzzle collection page
FIGURE 3.45: The puzzle collection page

The puzzle collection page allows you to play and replay the tactical puzzles in a given puzzle collection.

3.15.1 Blindfold mode

Blindfold mode can be enabled with the large blindfold toggle at the left of the PLAY button.

3.15.2 The toolbar

Button Description
The reset puzzles toolbar button Reset puzzles to their unsolved state.
TABLE 3.36: Toolbar buttons

3.16 The tactical puzzles page

The tactical puzzles page
FIGURE 3.46: The tactical puzzles page

The tactical puzzles page allows you to open a tactical puzzle collection.

Acid Ape Chess ships with three puzzle collections of increasing difficulty, and you can import a PGN file as a custom puzzle collection.

Pressing a puzzle collection opens the puzzle collection page.

3.16.1 The toolbar

Button Description
The import puzzle collection toolbar button Import a PGN file.
TABLE 3.37: Toolbar buttons

3.17 The rankings page

The rankings page
FIGURE 3.47: The rankings page

The rankings page displays:

3.17.1 Accessing the page

The rankings page can be accessed by using Online / OTB > Rankings in the main menu.

3.17.2 The OTB tab

The OTB tab displays the FIDE world rankings contained in the large Acid Ape Chess game database.

The player list can be filtered by name (using the search box), by sex (using the toolbar button) and by ELO (using the slider at the bottom of the tab). The sort order can be changed using the toolbar button.

Pressing a player opens the OTB player information page.

3.17.2.1 The toolbar

Button Description
The toggle favorites toolbar button Toggle between displaying all players or only favorite ones.
The cycle sex toolbar button Cycle the player sex filter.
The change sort order toolbar button Change the sort order.
TABLE 3.38: Toolbar buttons

3.17.3 The FICS, ICC and Lichess tabs

These tabs display the rankings of the respective chess server.

Pressing an user opens the user information page.

3.18 The relayed games page

The relayed games page
FIGURE 3.48: The relayed games page

The relayed games page lists OTB games relayed live by FICS.

3.18.1 Accessing the page

The relayed games page can be accessed by using Online / OTB > Relayed games in the main menu.

3.19 The server notifications page

The server notifications page
FIGURE 3.49: The server notifications page

The server notifications page displays the notifications received from FICS and ICC.

3.19.1 Accessing the page

The server notifications page can be accessed by using Online / OTB > Server notifications in the main menu.

3.19.2 Usage

When Acid Ape Chess is connected to FICS and/or ICC, it automatically records the server notifications it receives (even if the server notifications page is not opened).

Each server notification also triggers a title bar notification, unless you disable the SHOW IN TITLE BAR toggle in the page toolbar.

Some notifications can contain action buttons. For instance, a notification about an ongoing game will usually contain a button for observing the game.

3.20 The settings page

The settings page
FIGURE 3.50: The settings page

The settings page allows you to configure Acid Ape Chess.

3.20.1 Accessing the page

The settings page can be accessed by using Settings and help > General in the main menu.

3.20.2 Sections

3.20.2.1 General

Item Description
Sounds Toggle sounds.
Vibrations Toggle vibrations.
TABLE 3.39: General settings
Note
For usability reasons, sounds and vibrations are always enabled while the fullscreen clock is in use.

3.20.2.2 Board

Item Description
Theme Open the board theme page.
Display last move Toggle the last move arrow.
Display variations Toggle variation arrows.
Display eval gauge Toggle the eval gauge.
TABLE 3.40: Board settings

3.20.2.3 Players

Item Description
Manage players Open the player manager page.
TABLE 3.41: Players settings

3.20.2.4 Speech synthesis

Item Description
Always annunciate moves Toggle whether to always say opponent moves
TABLE 3.42: Speech synthesis settings
Note
If Always annunciate moves is off, opponent moves are only announced if a physical board is connected or if blindfold mode is enabled.

3.20.2.5 Chess engines

Item Description
Use online opening book Toggle whether to use the online opening book.
Display relative eval Toggle whether to display chess engine evaluations relative to the side to move.
TABLE 3.43: Chess engines settings
Note
The Display relative eval option does not affect auto annotation nor the eval gauge, both of which always use absolute evaluations (for better interoperability and readability).

3.21 The user information page

The user information page
FIGURE 3.51: The user information page

The user information page displays various informations about an user connected to FICS, ICC or Lichess.

3.21.1 Accessing the page

The user information page for a particular user can be accessed via Online / OTB > Players in the main menu.

In some cases, it can also be accessed by clicking the name of a player in the game information subpage.

Your own chess server profile can be accessed via Online / OTB > My profile in the main menu, or in some cases, by clicking your name in the game information subpage.

3.21.2 User information

Depending on the server and user, the following user information may be included:

  • the user handle;
  • the user type (registered or unregistered);
  • the time since the user has connected to the server;
  • the time the user has been idle;
  • whether the user has Timeseal support (FICS/ICC only);
  • the user ratings and statistics in various categories;
  • the game history of the user (games can be opened by pressing them);
  • the user notes.

3.21.3 The toolbar

Toolbar buttons are described below. Note that some of these buttons are only available for some user types and/or servers.

Button Description
The refresh toolbar button Refresh the user information.
The web toolbar button Open the user's web profile.
The challenge toolbar button Challenge the user.
The chat toolbar button Chat with the user.
The edit toolbar button Edit your profile notes.
TABLE 3.44: Toolbar buttons

4 Dialogs

Notable Acid Ape Chess dialogs include:

4.1 The time control selection dialog

The time control selection dialog
FIGURE 4.1: The time control selection dialog

The time control selection dialog allows you to select from predefined and custom time controls.

4.1.1 Accessing the dialog

The time control selection dialog can be accessed by pressing the settings button in the time selectors of the New Game page and of the play dialog.

4.1.2 Usage

  • To select a time control, press it.
  • To restore the associated UI control to the default time/increment selector, select the Custom entry at the top of the list.
  • To add a custom time control to the list, use the ADD button.
  • To edit or remove a custom time control, access its context menu by long-pressing the entry.
Note
Predefined time controls cannot be removed.

4.2 The time control properties dialog

The time control properties dialog
FIGURE 4.2: The time control properties dialog

The time control properties dialog allows you to add a custom time control to the list of the time control selection dialog, or to edit such a custom time control.

4.2.1 Accessing the dialog

4.2.2 Fields

Item Description
Name Provide a friendly name for the time control.
Spec Set the time control specification.
TABLE 4.1: Dialog fields

4.3 The play dialog

The play dialog
FIGURE 4.3: The play dialog

The play dialog allows you to create advanced chess engine games, engine duels and human duels.

While the New Game page allows you to create simple online games, engine games and simuls, the play dialog allows you to configure asymmetric clocks and use a custom initial position.

4.3.1 Accessing the dialog

The play dialog can be accessed by using Position > Play in the main menu.

4.3.2 The position selector

The position selector allows you to choose between the standard initial position and a randomly-generated Chess960 initial position.

Moreoever, if the play dialog is opened when the active page is a game data source, the position selector also includes the position of that game.

4.3.3 Side configurators

Each side configurator includes:

  • a player selector, for selecting a human or engine player;
  • if an engine that supports variable strength is selected, an engine strength selector;
  • if an engine that supports personalities is selected, an engine personality selector;
  • a time selector supporting simple and advanced time controls.

If the play dialog is opened when the active page is a game data source, the side configurators of the source position are initialized to convenient default values.

To swap the black and white configurations, use the flip button at the bottom of the dialog.

4.3.4 Blindfold mode

To play a blindfold game against a chess engine, enable the BLINDFOLD MODE toggle.

4.4 The New Position dialog

The New Position dialog
FIGURE 4.4: The New Position dialog

The New Position dialog allows you to create a scratch game page.

4.4.1 Accessing the dialog

The New Position dialog can be accessed by using Position > New in the main menu.

4.4.2 The position selector

The position selector allows you to choose between the standard initial position and a randomly-generated Chess960 initial position.

Moreoever, if the New Position dialog is opened when the active page is a game data source, the position selector also includes the position of that game.

4.5 The subpages layout selection dialog

The subpages layout selection dialog
FIGURE 4.5: The subpages layout selection dialog

The subpages layout selection dialog allows you to save and restore multiple game subpages layouts.

4.5.1 Accessing the dialog

The subpages layout selection dialog can be accessed by long-pressing a game subpage title.

4.5.2 Usage

  • To add the current subpages layout to the list and close the dialog, use the ADD button.
  • To apply a subpages layout to the current game page, press it.
  • To remove a subpages layout, access its context menu by long-pressing the entry.

4.6 The auto annotate dialog

The auto annotate dialog
FIGURE 4.6: The auto annotate dialog

The auto annotate dialog allows you to launch automatic annotation of the current game using a chess engine, endgame tablebases and some heuristics.

4.6.1 Accessing the dialog

The auto annotate dialog can be accessed by using Game > Auto annotate in the main menu or the auto annotate toolbar button of the game page.

4.6.2 Sections

4.6.2.1 General

Item Description
Engine Select the engine used for annotation.
Instances Set the number of engine instances that should be used concurrently.
Time per move Set the search time allocated to each move.
Total time Displays the estimated total computation time, computed from Instances, Time per move and the number of moves to annotate.
Follow progress Navigate to moves as they are annotated.
TABLE 4.2: General settings

4.6.2.2 Output

These toggle buttons allow you to enable or disable individual output items.

Item Description
Introduction Insert a PGN introduction comment before the first move.
Move annotation Add move quality annotations (!, !!, ? or ??) for moves that change the engine evaluation significantly or change the EGTB outcome.
Depth Add the engine search depth.
Score or mate Add the engine score (in pawns), or if a mate is found, the number of moves to reach it.
Engine best move Add the engine best move (if it differs from the move actually played).
EGTB result Add the EGTB result (white win, black win or draw) and best move.
Move comment Add a comment describing the quality of the move, for instance good move for the ! annotation.
TABLE 4.3: Output settings

4.6.3 Annotation examples

4.6.3.1 All output items enabled

78... Qc4?? 34/+1.03 [Qc3] [Qc3 -> EGTB black win] bad move

Part Description
?? This black move caused a significant change in the engine evaluation. This change was profitable to white.
34 The engine could search up to depth 34.
+1.03 According to the engine, white is now up by 103 centipawns.
[Qc3] The engine best move was Qc3.
[Qc3 -> EGTB black win] The EGTB best move was Qc3 and would have led to a win for black.
bad move A textual representation for ??.
TABLE 4.4: Annotation parts

4.6.3.2 White mate found

23. Rg3 128/12#

Part Description
128 The engine could search up to depth 128.
12# The engine has determined that white has a forced mate: black can be checkmated in 12 moves.
TABLE 4.5: Annotation parts

4.6.3.3 Black mate found

29. g7 50/-3#

Part Description
50 The engine could search up to depth 50.
-3# The engine has determined that black has a forced mate: white can be checkmated in 3 moves.
TABLE 4.6: Annotation parts

4.6.4 Limitations

Only the main line is annotated. Variations are currently ignored.

4.7 The engine settings dialog

The engine settings dialog
FIGURE 4.7: The engine settings dialog

The engine settings dialog allows you to configure chess engine settings.

4.7.1 Accessing the dialog

The engine settings dialog can be accessed from:

4.7.2 Sections

4.7.2.1 General

Note that some of these settings may be absent if the engine does not support them.

Item Description
Name Modify the name provided by the engine.
Working directory Set the directory the engine is started in.
Cores Use a specific number of CPU cores.
Think on opponent's time Use pondering.
Use online opening book Use the online opening book.
TABLE 4.7: General settings
Note
Setting the working directory can be useful if the engine searches for its data files in the current directory (many engines do), and if you have transferred data files (opening books, endgame tablebases, etc) to your device for use by the engine.

4.7.2.2 Engine-specific

The options advertised by the engine are listed in this section.

4.8 The physical board settings dialog

The physical board settings dialog
FIGURE 4.8: The physical board settings dialog

The physical board settings dialog allows you to configure physical board and physical clock handling.

4.8.1 Accessing the dialog

The physical board settings dialog can be accessed by pressing the settings button in the physical board page.

4.8.2 Board Settings

Item Description
Stabletime delay Modify the stabletime delay.
TABLE 4.8: Physical board settings

4.8.3 Clock Settings

Item Description
Sounds Toggle physical clock sounds.
Display last move Display the opponent move on the physical clock.
Display moves in capitals Display moves in capital letters. On a DGT3000, this is usually more readable than the standard notation.
TABLE 4.9: Physical clock settings

5 Features

Notable Acid Ape Chess features are detailed in this chapter.

5.1 Inter page communication

Game data is implicitly shared between certain pages and dialogs.

The following sections describe the mechanisms involved in this process.

5.1.1 Game data sources and sinks

A game data source is a page which exports one or more game data items for use by a game data sink.

A game data sink is a page or dialog which imports one or more game data items from the current game data source (i.e. from the currently displayed page).

Game data items are:

  • the displayed position;
  • the game tree and properties;
  • the state of the board flipped toggle.

5.1.1.1 List of game data sources

The following pages are game data sources:

5.1.1.2 List of game data sinks

The following pages or dialogs are game data sinks:

5.1.2 Example 1: edit a position

To open the currently displayed position of a game page in a new position editor page, simply use Position > Edit in the main menu.

This uses the currently displayed game page (the current game data source) to initialize a newly created position editor page (the game data sink) with the currently displayed position and the board flipped state.

5.1.3 Example 2: analyze an edited position

To analyze the currently edited position of a position editor page in a new game page, simply use Position > Analyze in the main menu.

This uses the currently displayed position editor page (the game data source) to initialize a newly created scratch game page (the game data sink) with the currently edited position and the board flipped state, then start analysis in that game page.

5.1.4 Example 3: analyze a physical board position

To analyze the current position of a physical board page in a new game page, simply use Position > Analyze in the main menu.

This uses the currently displayed physical board page (the game data source) to initialize a newly created scratch game page (the game data sink) with the current physical board position, then start analysis in that game page.

5.2 Time controls

Acid Ape Chess provides a wide range of predefined time controls. You can also add custom time controls supporting multiple periods, move limits and Fischer increments.

5.2.1 Format

Acid Ape Chess supports a commonly used, de facto standard for expressing time controls.

A time control specification consists of one or more period specifications separated by space characters.

5.2.1.1 Period format

A period specification can have multiple formats.

Format Description
n Unlimited moves in n minutes.
n+i Unlimited moves in n minutes, with i seconds added after each move (Fischer increment).
m/n m moves in n minutes.
m/n+i m moves n minutes, with i seconds added after each move (Fischer increment).
TABLE 5.1: Period specification formats
Note
If m is G or SD, sudden death is used. Such a period can only be the last period.

5.2.1.2 Time control requirements

  • there must be at least one period;
  • there must be at most one sudden death period;
  • a sudden death period must follow the last limited move period (if any).

5.2.1.3 Examples

Specification Description
1 1 minute for the entire game, with no increment.
3+2 3 minutes for the entire game, with 2 seconds added after each move (Fischer increment).
5+0 5 minutes for the entire game, with no increment.
40/90+30 G/30+30 90 minutes for the first 40 moves (with 30 seconds added after each move), then 30 extra minutes for the rest of the game (with 30 seconds added after each move).
TABLE 5.2: Time control specification examples

5.2.2 Predefined time controls

Name Spec Description
Custom N/A Use a custom time and Fischer increment selector.
Blitz 3+2 Often used in FIDE-sanctioned blitz tournaments.
Rapid 15+10 Often used in FIDE-sanctioned rapid tournaments.
Classical 40/90+30 G/30+30 Often used in FIDE-sanctioned classical tournaments.
Classical Online 120+30 Because online chess servers do not support advanced time controls.
World Championship 40/100+30 20/50+30 G/15+30 Used in the classical games of the World Chess Championship.
World Championship Rapid Tie Break 25+10 Used in the rapid tie breaks of the World Chess Championship.
World Championship Blitz Tie Break 5+3 Used in the blitz tie breaks of the World Chess Championship.
Armageddon White 60/5 G/0+3 Often used by white in Armageddon tie breaks.
Armageddon Black 60/4 G/0+3 Often used by black in Armageddon tie breaks.
TABLE 5.3: Predefined time controls

5.3 Offering or claiming draws

Pressing a draw button offers a draw to the opponent unless:

The arm feature is in accordance with the following rules of the FIDE Laws of Chess:

5.4 Endgame tablebases

Acid Ape Chess provides instant access to Syzygy 7-men endgame tablebases.

When analysis is enabled and there are 7 or less pieces left on the board, Acid Ape Chess queries the Syzygy 7-men online service and displays the EGTB result as an extra move arrow.

Endgames tablebases can also be used to auto annotate compatible positions.

5.5 Chess960

Chess960, also called Fischer Random Chess, is a chess variant that randomizes home ranks pieces.

5.5.1 Enabling Chess960 mode

The New Game page has a toggle for enabling Chess960.

Some dialogs (such as the New Position dialog and the play dialog) feature a position selector with a random initial Chess960 position.

5.6 Blindfode mode

Acid Ape Chess supports blindfold play:

5.6.1 Enabling blindfold mode

The New Game page, the puzzle collection page and the play dialog have a toggle button for enabling blindfold mode.

5.7 Speech recognition

Acid Ape Chess uses move speech recognition in blindfold mode and when the recognize move button of the move list subpage is used.

5.7.1 Caveats

Our move speech recognition algorithm was trained with US english speakers, so the recognition success rate may vary with your accent and pronunciation.

We are working on improving this algorithm.

5.8 Online chess servers

Acid Ape Chess has extensive first-class support for FICS, ICC and Lichess.

This allows you to:

5.9 Chess engines

Acid Ape Chess supports UCI and CECP chess engines, and ships with these built-in engines:

With a chess engine, you can:

5.9.1 Adding engines

If you have installed apps that export their chess engines via the Open Exchange protocol (a de facto standard on Android, used by numerous third-party engine apps), Acid Ape Chess automatically detects and registers these engines.

You can add engine apps or binaries using the add toolbar button in the ENGINE or SIMUL tab of the New Game page, or in the engine manager page.

The resulting dialog proposes a few popular chess engine apps and also allows you to add an engine binary from device storage or the SD Card.

5.9.1.1 Engine license activation

Some commercial engines require manual license activation after installation. If this is the case and activation has not been performed, Acid Ape Chess cannot register the engine.

Activation is usually performed by launching the separate engine app once. Consult your engine documentation for details.

5.9.2 CPU core allocation

Acid Ape Chess reserves one CPU core for other tasks (the system, the Acid Ape Chess UI, other apps) and evenly shares the remaining cores amongst the engines running in a game page.

For instance, if your phone has 8 cores:

  • analyzing with one engine (or playing against an engine) will allocate 7 cores to the engine;
  • analysis with two engines (or creating an engine duel) will allocate 3 cores to each engine.
Warning
This core allocation algorithm is per-task, not app-global (a task is a game or an analysis). This means that if you run multiple chess engine tasks simultaneously, you might exceed your device processor and/or memory capabilities (if your device becomes overloaded, it might freeze for long periods while trying to recover).

You can force an engine to use a specific number of cores via the engine settings dialog. Note that this only has effect for human vs engine games. Analysis, simuls and engine duels ignore this setting.

5.9.3 Battery usage

A chess engine uses your system to its full capacity and therefore drains your battery fast.

Chess engines continue to run while Acid Ape Chess is in the background, so that you can use other apps while analysis is running or while a chess engine is thinking during a game.

If chess engines are running while Acid Ape Chess is in the background, a system notification appears to remind you about battery usage. Pressing the Close button of the notification terminates the engines.

5.10 Simuls

Acid Ape Chess allows you to play against multiple chess engines simultaneously.

This mimics real life simultaneous exhibitions and is an interesting way to play some chess.

5.10.1 Creating a simul

To create a simul, use the New Game page's SIMUL tab.

5.10.2 Simul rules

In a simul:

  • you play with White;
  • you have unlimited time;
  • each opponent is forced to play his move shortly after you arrive at his board.

5.11 The Acid Ape Chess game database

The Acid Ape Chess online game database is maintained by Acid Ape Studios and provides:

This database is updated continuously.

5.11.1 Uses

The online game database is used by:

5.12 The online opening book

The Acid Ape Chess online opening book is maintained by Acid Ape Studios and uses the online game database.

It can be used to feed chess engines with good opening moves.

Some chess engines (such as Arasan or cheng4) already ship with their embedded opening book, so you might want to enable this feature only for engines that do not have an opening book.

5.12.1 Enabling the feature

The online opening book can be enabled:

If the global setting is enabled, it takes precedence over individual engine settings.

5.12.2 Chess engine support

The online opening book is only supported by UCI engines.

5.13 Physical board support

Acid Ape Chess allows you to play on a connected physical chessboard.

A physical clock can optionally be connected to that board.

5.13.1 Supported physical boards

Model Connection
DGT Bluetooth e-Board Bluetooth, USB
DGT USB e-Board USB
DGT Smart Board USB
DGT Revelation II Bluetooth, USB
TABLE 5.4: Supported physical boards

In addition to the listed models, Acid Ape Chess is also compatible with any electronic board or adapter implementing the DGT protocol.

For instance, an inventive user has connected a Novag Citrine chessboard to Acid Ape Chess by using a DGT adapter.

5.13.2 Connecting to a physical board

5.13.2.1 Connecting to a Bluetooth board

To connect to a Bluetooth board, use the physical board page.

5.13.2.2 Connecting to an USB board

To connect to an USB board, simply plug the board into your phone or tablet. You can also use the physical board page to test your board once it is connected.

Note
Make sure that the OTG side of your cabling is plugged into your phone or tablet.

5.13.3 Highlighted squares

When a physical board is connected, specific squares may be highlighted on the Acid Ape Chess virtual board.

5.13.4 Advanced features

5.13.4.1 Stabletime

The stabletime feature causes Acid Ape Chess to wait for the board to stabilize before considering a change.

It is used to avoid misdetection of sliding in double-step pawn advances and bishop/rook/queen moves.

The wait delay defaults to 400 ms and can be modified from the physical board settings dialog.

The algorithm is smart enough and inhibits itself when a move can not be further extended.

For instance, when playing 1. e3, the stabletime delay is in effect because the move can further be extended to 1. e4. However, when the e4 square is reached, the move is applied immediately because it can not be further extended.

5.13.4.2 Result encoding with kings on center

The result of a game can be encoded by placing the kings on two of the center squares (d4, d5, e4 and e5).

Note
To use this encoding feature, make sure that the first king move is an illegal move. If it is not, first remove both kings before placing them back in the center squares.
5.13.4.2.1 White win

To encode a white win, place both kings on light squares: d5 and e4.

5.13.4.2.2 Black win

To encode a black win, place both kings on dark squares: d4 and e5.

5.13.4.2.3 Draw

To encode a draw, place both kings on squares of opposite colors: d4 and e4, d5 and e5, d5 and d4, or e5 and e4.

5.14 Physical clock support

When a chess clock is connected to a supported physical board, Acid Ape Chess displays its internal game clock on the physical clock.

Moreover, a physical clock is a tap input source for external clock mode.

5.14.1 Supported physical clocks

5.14.1.1 The DGT3000

Acid Ape Chess supports the DGT3000 connected to any DGT board model.

5.14.1.1.1 Connecting to a DGT3000
  1. Connect the DGT3000 to your chessboard.
  2. Select Option 25 on your DGT3000.
  3. Press the rightmost button on your DGT3000 to confirm Option 25.
  4. Connect Acid Ape Chess to your chessboard.
  5. Use the physical board page to verify that the DGT3000 is recognized by Acid Ape Chess.
Note
When connected to a DGT Smart Board, the position of the DGT3000 turn lever is not updated in the physical board page. However, the lever position is properly detected during a game.
5.14.1.1.2 DGT3000 buttons

Some DGT3000 buttons control Acid Ape Chess features.

Button Description
The DGT3000 button 1 Unassigned.
The DGT3000 button 2 Toggle the clock beeper.
The DGT3000 button 3 Start, pause or resume the game.
The DGT3000 button 4 Unassigned.
The DGT3000 button 5 Unassigned.
TABLE 5.5: DGT3000 clock buttons
Note
The button 2 toggles the Acid Ape Chess clock beeper, both for the Android device and for the DGT3000. To toggle DGT3000 sounds independently, use the Sounds option in the physical board settings dialog.
5.14.1.1.3 Clock lag

Acid Ape Chess requires the use of Option 25 on the DGT3000, and in this option, the DGT3000 is a bit laggy (your taps might sometimes be sent by the clock a few seconds after they occur). There is less lag when the clock is connected to a DGT Smart Board, but it is still problematic in blitz games.

In a future version of Acid Ape Chess, this issue will be eliminated by allowing the DGT3000 to be the time source of Acid Ape Chess (and not just the other way around as it is the case right now).

5.14.1.2 The DGT Pi

Acid Ape Chess supports the DGT Pi, as the DGT Pi can be used as a regular DGT3000 clock. For more details, consult the DGT Pi manual.

5.15 The fullscreen clock

The fullscreen clock
FIGURE 5.1: The fullscreen clock

When playing OTB games with a physical board but no physical clock, the fullscreen clock can be used as a virtual clock that players must tap to confirm their move (the fullscreen clock is a tap input source for external clock mode).

5.15.1 Accessing the fullscreen clock

The fullscreen clock can be enabled by pressing the FULLSCREEN CLOCK button of the game information subpage (on smaller screens, you might have to scroll the subpage down a bit to reach that button).

This button only appear when relevant (you don't want a fullscreen clock if you have to input the moves with the virtual board).

5.15.2 Action buttons

The central area contains a number of action buttons (which may or may not be present depending on the game context).

Button Description
The play action Start or resume the game.
The pause action Pause the game.
The resign action Resign the game.
The draw action Offer or claim a draw.
The draw armed action Claim a draw after next move.
The rematch action Offer a rematch.
The flip action Flip the clock.
The sound action Toggle the clock beeper.
The autoflag action Toggle autoflagging.
TABLE 5.6: Action buttons

5.15.3 Status icons

5.15.3.1 Top center

When a physical clock is connected, the top center status icon appears.

Icon Description
The clock turn left status icon A physical clock is connected and its lever is up on the left side.
The clock turn right status icon A physical clock is connected and its lever is up on the right side.
TABLE 5.7: Top center status icons

5.15.3.2 Bottom center

When a physical board is connected, the bottom center status icon appears.

The status icon when a DGT board is connected
FIGURE 5.2: The status icon when a DGT board is connected

5.15.3.3 Side-specific

Side-specific status icons may appear in the lower left or lower right corner of the clock.

Icon Description
The clock turn left side status icon The left side played a legal move but did not yet confirm it by a clock tap.
The clock turn right side status icon The right side played a legal move but did not yet confirm it by a clock tap.
The flag side status icon The side has lost on time.
The board error side status icon The physical board position differs from the Acid Ape Chess board position. Fix the physical position.
TABLE 5.8: Side-specific status icons

Additionally, if a side's time control has multiple periods, the current period number for that side is indicated near the bottom center part of the screen.

5.16 External clock mode

External clock mode requires the use of a physical or virtual chess clock to:

External clock mode is enabled when all of the following conditions are true:

A move arrow indicates a legal move that has been played on the chessboard but not yet confirmed by a clock tap.

5.17 Game autosaving

Acid Ape Chess automatically saves played, adjourned and observed games.

Your saved games can be reached with the PGN explorer page.

5.17.1 Autosave locations

Games of different types are saved in different locations.

In the following table the listed files are relative to Internal storage/Acid Ape Chess/Games, which is the Home location of the PGN explorer page.

Location Description
My games.pgn Your online and engine games.
My adjourned games.pgn Your adjourned games.
My simuls Your simuls.
Human duels.pgn Your OTB games.
Engine duels.pgn The engine duels you have organized.
Observed games.pgn Your observed games.
TABLE 5.9: Game autosave locations

5.18 Game adjournment

You can adjourn engine games and human duels, and resume playing at a later time.

Your adjourned games are autosaved to My adjourned games.pgn and can be reached with the PGN explorer page.

5.18.1 Adjourning a game

To adjourn a game in progress, quit the game by pressing the Back button. If the game type supports adjournment, the quit dialog will feature an ADJOURN button in addition to the RESIGN button.

Press the ADJOURN button to mark the game as adjourned and save it to My adjourned games.pgn. The game page will then be closed.

5.18.2 Resuming an adjourned game

To resume an adjourned game, reach the adjourned game with the PGN explorer page, then press on the game.

Note
Finished games are automatically removed from My adjourned games.pgn.

5.19 Game sharing

Acid Ape Chess allows you to share your games as downloadable PGN files.

5.19.1 How to share a game

To share the current game, use Game > Share in the main menu.

5.19.2 Operation

When you share a game, Acid Ape Chess uploads the PGN file to its backend server, which replies with an unique download link for the PGN file.

This download link is then shared with the standard Android share mechanism.

6 Tasks

This chapter describes how to perform some typical tasks.

6.1 Online tasks

6.1.1 Play an unrated online game

  1. Switch to the New Game page (it is the startup page).
  2. Switch to the ONLINE tab.
  3. Select your desired color and time controls.
  4. Select the chess account of your choice.
  5. Press the PLAY button.

6.1.2 Play a rated online game

  1. Switch to the New Game page (it is the startup page).
  2. Switch to the ONLINE tab.
  3. Select your desired color and time controls.
  4. If needed, add an authenticated chess account (one with an username and password) using the add button in the toolbar.
  5. Select the authenticated chess account of your choice.
  6. Enable the cup toggle button (at the left of the PLAY button).
  7. Press the PLAY button.

6.1.3 Play against a friend who is also using Acid Ape Chess

  1. Ask your friend to select Online OTB > My profile in the main menu.
  2. Ask him to select the FICS tab and let you know his user name.
  3. Select Online / OTB > Players.
  4. Select the FICS tab.
  5. Use the search box to search for your friend.
  6. Press on your friend username.
  7. Press on the challenge button in the bottom toolbar.
  8. Configure the challenge and press the OK button.

6.1.4 Play against a friend who is not using Acid Ape Chess

  1. Ask your friend to connect to FICS and let you know his user name.
  2. Select Online / OTB > Players.
  3. Select the FICS tab.
  4. Use the search box to search for your friend.
  5. Press on your friend username.
  6. Press on the challenge button in the bottom toolbar.
  7. Configure the challenge and press the OK button.

6.1.5 Watch a live online game

  1. Select Online / OTB > Games in the main menu.
  2. Select the desired chess server tab.
  3. Select a game from the list.

6.2 Engine tasks

6.2.1 Play an engine game

  1. Switch to the New Game page.
  2. Switch to the ENGINE tab.
  3. Select your desired color and time controls.
  4. Select the engine of your choice.
  5. Press the PLAY button.

6.2.2 Create an engine duel

  1. Select Position > Play in the main menu.
  2. Select the desired engines for black and white.
  3. Press the OK button.

6.2.3 Play against an engine having a material handicap

  1. Select Position > Edit in the main menu.
  2. Edit the position to match the handicap of your choice.
  3. Select Position > Play in the main menu.
  4. Select the desired engine for the side having the handicap.
  5. Select a human player for the other side.
  6. Press the OK button.

6.2.4 Play against an engine having a time handicap

  1. Select Position > Play in the main menu.
  2. Select the desired engine for one side.
  3. Select a human player for the other side.
  4. Use the white or black time controls to set the desired handicap.
  5. Press the OK button.

6.2.5 Save a material handicap for later use

  1. Select Position > Edit in the main menu.
  2. Edit the position to match the handicap of your choice.
  3. Select Game > Save in the main menu.
  4. Select a location and file name, then press SAVE.

6.2.6 Load and play a handicapped position

  1. Select Game > Explorer in the main menu.
  2. Open the previously saved file containing your handicapped position.
  3. Select Position > Play in the main menu.
  4. Select the desired engine for the side having the handicap.
  5. Select a human player for the other side.
  6. Press the OK button.

6.3 OTB tasks

6.3.1 Watch a live OTB game

  1. Select Online / OTB > Relayed games in the main menu.
  2. Select a game from the list.

6.3.2 Connect a DGT chessboard via Bluetooth

  1. Select Settings and help > e-Board in the main menu.
  2. Press SCAN DEVICES.
  3. After a few seconds, your Bluetooth chessboard should be found. Click on it.

6.3.3 Connect a DGT chessboard via USB

  1. Connect your chessboard to your phone with an USB OTG cable.
  2. If Android detects that an USB device handled by Acid Ape Chess was connected, the system automatically launches Acid Ape Chess.
  3. Acid Ape Chess automatically connects to the chessboard.
  4. To test your chessboard, select Settings and help > e-Board in the main menu.

6.3.4 Record an OTB game

  1. Connect to a physical chessboard.
  2. Select Position > Play in the main menu.
  3. Configure Black and White to be human players.
  4. Press the OK button.
  5. If a physical clock is connected, press the play/pause button on the clock (see external clock mode).
  6. Play the game to its completion so that it is autosaved.