Checkers[note 1] (American English), also known as draughts (/drɑːfts, dræfts/; British English), is a group of strategy board games for two players which involve forward movements of uniform game pieces and mandatory captures by jumping over opponent pieces.

American checkers was weakly solved in 2007 by a team of Canadian computer scientists led by Jonathan Schaeffer.

Multiple enemy pieces can be captured in a single turn provided this is done by successive jumps made by a single piece; the jumps do not need to be on the same diagonal and may "zigzag" (change diagonal direction).

In these languages, the queen in chess or in card games is usually called by the same term as the kings in checkers.

A case in point includes the Greek terminology, in which checkers is called "ντάμα" (dama), which is also one term for the queen in chess.

[3] In the British Museum are specimens of ancient Egyptian checkerboards, found with their pieces in burial chambers, and the game was played by the pharaoh Hatshepsut.

[8] Al qirq was brought to Spain by the Moors,[9] where it became known as Alquerque, the Spanish derivation of the Arabic name.

[3] The rule of crowning was used by the 13th century, as it is mentioned in the Philippe Mouskés's Chronique in 1243[3] when the game was known as Fierges, the name used for the chess queen (derived from the Persian ferz, meaning royal counsellor or vizier).

[11] The rule forcing players to take whenever possible was introduced in France in around 1535, at which point the game became known as Jeu forcé, identical to modern American checkers.

[3][12] The game without forced capture became known as Le jeu plaisant de dames, the precursor of international checkers.

[4] American checkers (English draughts) has been the arena for several notable advances in game artificial intelligence.

More recently, in 2007 scientists at the University of Alberta[25] developed their "Chinook" program to the point where it is unbeatable.

In November 1983, the Science Museum Oklahoma (then called the Omniplex) unveiled a new exhibit: Lefty the Checker Playing Robot.

Programmed by Scott M Savage, Lefty used an Armdroid robotic arm by Colne Robotics and was powered by a 6502 processor with a combination of Basic and Assembly code to interactively play a round of checkers with visitors to the museum.

Originally, the program was deliberately simple so that the average museum visitor could potentially win, but over time was improved.

And if a polynomial bound is placed on the number of moves that are allowed in between jumps (which is a reasonable generalisation of the drawing rule in standard Checkers), then the problem is in PSPACE, thus it is PSPACE-complete.

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