Buff and Green is an implementation of a game also known as Checkers, Draughts, Dama, Damas, Dame. If the name Buff and Green is used then this specific implementation is meant. The other names are used here to refer to the game in more general scope. Like when discussing specific rule variants or if the whole family of Checkers games is meant. The family of Checkers games is played on rectangular game boards and game pieces called checkers. These are placed and moved on squares representing the game board. Checkers claims to be a successor of Alquerque. Alquerque is a medieval Spanish board game. Both, Checkers and Alquerque, are 2-player, abstract, strategic, perfect information, traditional board games. Due to the variants and differences in applied rules in the family of Checkers games the rules for Buff and Green are discussed and selected from the given variety.

Objective of the game is to be the last player performing a valid move according to the rules. Meaning the player being not able to move will lose the game. This may occur when either all own checkers have been captured by the opponent or all remaining own checkers have no valid moves left.

Draw situations might occur.

Players' turns alternate between players. The player controlling dark checkers moves first in Buff and Green. A player either

• must capture opponent’s pieces if possible or
• must perform a normal non-capturing move otherwise.

Passing a turn is not allowed.

A Checker's non-capturing move is performed by moving the checker in diagonally forward direction onto a free adjacent board position. A non-capturing move of a Checker is not allowed in diagonally backwards direction.

Kings move by performing long jumps. A King moves in any diagonally forward and diagonally backward direction in straight line passing any amount of free board positions. A King's move ends on such a free board position then.

A checker reaching the base row of the opponent on the far side of the game board by a non-capturing move it is promoted to king status.

If a checker is reaching this far side of the game board by performing a capture and is still able to consecutively capture as a checker it must perform the capture without being promoted to king.

Capturing is mandatory. A checker of your color captures an opponent's game piece being adjacent to your checker by jumping directly behind it onto a free adjacent board position in straight line diagonally.

Capturing is allowed in any valid diagonally forward and diagonally backward direction. Only a single opponent's game piece can be captured at a time.

The captured opponent's checker or king is removed immediately while the capture takes place.

If the capturing game piece is able to consecutively perform further capturing from it's target board position the player must continue to capture with this game piece.

Kings perform long jump captures. ...

On availability of multiple consecutive capturing paths on a player's turn it is not necessary to capture on the longest capturing path. The player can freely choose among given capturing paths but still has to continue capturing until no further capture is available on a path.

Tests can be started by visiting https://omerkel.github.io/Buff-and-Green/html5/test/test_buffngreen.html

The tests cover behavior of

• the board representing the data model of Buff and Green.
• the move generator finding valid moves for a board situation according to the implemented rules.

• jQuery: MIT licensed, https://github.com/jquery/jquery
• jQuery Mobile: MIT licensed, https://github.com/jquery/jquery-mobile
• QUnit: MIT licensed, https://github.com/qunitjs/qunit

• Association for the Advancement of Artificial Intelligence, http://www.aaai.org
• HTML Living Standard, Web Workers, https://html.spec.whatwg.org
• Portable Draughts Notation (PDN) 3.0 standard 1.0 documentation, http://pdn.fmjd.org

Mind that official tournament rules of the listed organizations differ from each other. Buff and Green is independent development from any work of these organizations.

• Official FMJD tournament rules of International Draughts, https://fmjd.org/?p=annex
• Official FMJD Section 64 IDF tournament rules of Draughts-64, https://fmjd64.org/rules-of-the-game
• Official Confederação Brasileira de Jogo de Damas tournament rules of Brazilian Draughts, http://www.codexdamas.com.br/english_rules.html
• FMJD published rules of Turkish Dama, http://www.fmjd.org/downloads/td/TD_eng.pdf
• Official WCDF tournament rules of Draughts-64, http://www.wcdf.net/rules/rules_of_checkers_english.pdf
• Official APCA tournament rules of American Pool, http://www.americanpoolcheckers.us/americanpoolcheckers/index.php/history/apca-tournament-rules-of-play

Mind that official tournament rules of the listed organizations differ from each other. Buff and Green is independent development from any work of these organizations.

• Fédération Mondiale du Jeu de Dames (FMJD), http://www.fmjd.org , founded in 1947
  • Variants listed at FMJD: 100 International, 64 Brazilian, 64 Checkers, 64 Czech, 64 Italian, 64 Pool, 64 Russian, 64 Spanish, 144 squares, Turkish Dama
• World Draughts Federation (Federation Mondiale Du Jeu De Dames) FMJD Section 64, https://fmjd64.org , accepted section in FMJD since 1984
• The International Draughts Federation (IDF), https://fmjd64.org/idf , founded in 2012 / 2013
• Confederação Brasileira de Jogo de Damas (CBD), http://www.codexdamas.com.br
• World Checkers Draughts Federation (WCDF), http://www.wcdf.net
• American Pool Checkers Association (APCA), http://americanpoolcheckers.us

• Oliver Merkel

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