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Arimaa Challenge[edit]

The Arimaa challenge was won in 2015, when the bot Sharp won matches against three top human players.


A piece that is not frozen, and yet still unable to move is blockaded. This occurs when it is surrounded by pieces that it cannot push out of the way. See also Immobilization, Frame.


The second strongest of the six unique Arimaa pieces.


See Trap (verb).


The fifth strongest of the six unique Arimaa pieces.


When a player's own Rabbit is used against them to help blockade a major piece. This is done by placing the Rabbit behind the major piece so that the Rabbit blocks movement in that direction. The major piece is said to be choked.


The fourth strongest of the six unique Arimaa pieces.


Moving an opponent's piece either by pushing or pulling.


Prior to July 1, 2008 an Arimaa game was said to be drawn if neither player has any Rabbits remaining on the board. Draws are no longer possible due to the introduction of elimination.

East Wing[edit]

The right side of the board viewed from Gold's perspective, specifically the f-, g-, and h-files.


The strongest of the six unique Arimaa pieces. The Elephant is the only piece that cannot be pushed or pulled by the enemy.


A player wins the game by elimination if the opposing player has no Rabbits left.


Occurs when each side traps a piece of equal strength, usually within a short period of time. For example, if each side captured a Rabbit on consecutive moves it is described as a Rabbit Exchange. See also Trap (verb).

False Protection[edit]

When two pieces adjacent to a trap appear to be mutually protected, but in fact, both are in danger of being trapped due to strong enemy pieces adjacent to them. See also Mutual Protection.


When an opponent's piece is frozen and partially blockaded such that if unfrozen the only step it could take is into an unprotected trap.


One of eight columns on an Arimaa board. From Gold's perspective, the a-file is on the left and the h-file is on the right. It is the opposite from Silver's perspective.


The combination of pulling and pushing an opponent's weaker pieces such that the weaker piece appears to be flipped to a different side of the stronger piece. Weaker pieces are vulnerable to being flipped to the opponent's side and eventually being trapped. Two special cases are sometimes called Swing and Throw.


A fork occurs if a piece is simultaneously threatened with capture in two different traps. This can only occur on the squares c4, c5, d3, d6, e3, e6, f4 and f5.


A four-step move making a change to the position which can be undone in two steps by the opponent. Four-for-twos are seldom good moves.


A piece which is on a trap square, surrounded on three sides by opposing pieces which prevent it from pushing its way off the trap square, has been framed. See also Pin and Trap (noun).


A piece is frozen if it is adjacent to a stronger enemy piece and is not adjacent to any friendly pieces. A frozen piece cannot move until the enemy piece moves away or a friendly piece moves onto an adjacent square.


A player wins the game by goal if one of his/her Rabbits advances to the opponent's home rank.


The player with the Gold pieces is both the first to setup and the first to move. See also Silver.

Home Trap[edit]

A trap on a player's third rank. The squares c3 and f3 are Gold's home traps; the squares c6 and f6 are Silver's home traps,


The third strongest of the six unique Arimaa pieces.


A piece that is frozen 2 squares away from a trap square is a hostage. If the trap is undefended, and the hostage-holder is mobile, the hostage piece can be trapped in one move.


A player wins the game by immobilization if the opposing player has no pieces remaining or is unable to make a single legal move. See also Blockade


When a player uses two or more pieces to take control of an opponent's home trap by not allowing the opponent access to three or all four squares adjacent to the trap. The opponents pieces near that trap usually scatter. See also Scatter.


The most exposed piece helping to hold a blockade or frame.

Lemming Mode[edit]

When a computer program gets triggered to sacrifice a series of minor pieces such as Rabbits, Cats or Dogs to prevent a stronger hostage piece such as a Horse or Camel from being captured. Typically the computer will recognize that the strong piece is in danger and send over a weak piece to try to help, only to have the weak piece captured with nothing to show for it. The cycle then repeats, with the computer repeatedly sending over weak pieces and the opponent repeatedly capturing them.


A formation usually at the edge of the board where two friendly pieces are diagonal to one another such that if either is pulled one step it remains unfrozen due to the other friendly piece and can easily return to its original place.

Major Piece[edit]

The major pieces in Arimaa are the Elephant, Camel, and Horse.

Minor Piece[edit]

The minor pieces in Arimaa are the Dog, Cat, and Rabbit.


See Turn.

Mutual Protection[edit]

When two or more pieces adjacent to a trap prevent each other from being trapped by stronger enemy pieces. See also False Protection.


A major piece (usually an Elephant) is said to be overloaded if it must simultaneously protect multiple friendly pieces at two different traps.


A major piece (usually an Elephant) is said to be overwhelmed if a group of weaker enemy pieces work together such that it is not able to trap any of them.


A lone friendly piece that is supporting a framed piece is said to be pinned. See also Frame.


When group of friendly pieces come together and form a T shape to prevent a stronger enemy piece from pushing the weaker piece at the top center of the T.

Postal Game[edit]

A slow game in which the players are allowed a specified number of days (sometimes hours) to complete each move. Historically postal games (e.g. chess, go) were played by old-fashioned mail and a single game could last for years. Nowadays, postal games are normally played online in a period of weeks or months. Also known as a correspondence game.


A player can pull an enemy piece with a stronger piece by first moving the friendly piece to one of the unoccupied adjacent squares and then moving the opponent's piece into the square that was just vacated. A pull requires 2 steps. See also Step.

Pull and replace[edit]

A four-step move where a strong piece pulls an opponent's piece, and a weak friendly piece occupies its former position, with the strong piece returning to its initial square.


A player can push an enemy piece with a stronger friendly piece by first moving the opponent's piece to one of the adjacent squares and then replacing it with the friendly piece. A push requires 2 steps. See also Step.

Push and replace[edit]

A somewhat less common variant of pull and replace.


A quarter of the board (16 squares), usually distinguished either by the trap square it contains, or by compass directions from the perspective of Gold. Thus the c6-quadrant is also the northwest quadrant, etc.


The weakest unit on the board and the only piece that cannot move backwards. However, Rabbits are extremely important due to their ability to win the game by goal. See also Goal.


One of eight rows on an Arimaa board. Gold begins the game with 16 pieces on the first and second ranks while Silver beings with 16 pieces on the seventh and eighth ranks. The home rank for Gold is 1, while Silver's is 8.


When a piece involved with holding a blockade or frame is freed to move by replacing it with another (usually weaker) friendly piece. Also referred to as rotation.


If a player allows a friendly piece to be trapped in order to pursue a strategic objective elsewhere on the board, the friendly piece is said to be sacrificed.


When a player's home trap is invaded the pieces near that trap move away to avoid being captured. See also Invade.


The opening phase of the game during which Gold then Silver places the pieces on their first 2 rows, respectively.


The player with the Silver pieces is second to setup the pieces and second to move. See also Gold.


A player may use between one and four steps on any turn. Moving a piece requires one step, while an additional step is required for a push or pull (a total of two steps).


There are six unique types of pieces, each with a different strength. Stronger units can push, pull and freeze any weaker enemy pieces. From strongest to weakest, the units are Elephant, Camel, Horse, Dog, Cat, Rabbit. See also Freeze, Pull, Push.


When a group of pieces advance together to overwhelm or blockade a stronger enemy piece.


The combination of pulling and pushing an opponent's weaker pieces such that the weaker piece is moved 90 degrees clock wise around the stronger piece. See also Throw and Flip.


Three steps making a change to the position which can be undone in one step by the opponent. Three-for-ones are usually not good moves.


Three steps making a change to the position which can be undone in three steps by the opponent. If this happens, both players are effectively making one-step moves, since the three reversible steps can be ignored. This may continue for several moves.


The combination of pulling and pushing an opponent's weaker pieces such that the weaker piece is moved 90 degrees counter clock wise around the stronger piece. See also Swing and Flip.

Trap (noun)[edit]

There are 4 trap squares on the board located at c3, c6, f3 and f6. Pieces that occupy these four squares may be trapped. See also Trap (verb).

Trap (verb)[edit]

A piece is trapped and removed from the board if it occupies a trap square and there are no friendly pieces occupying any of the four adjacent squares. If there is a friendly piece on an adjacent square, then it is possible for a second piece to safely walk over - or occupy - on a trap square. A trapped piece can also be described as being captured. See also Trap (noun).


A player completes a turn by moving pieces a total of one, two, three or four legal steps. The opposing player then makes his/her turn. Also known as a move. See also Step.

West Wing[edit]

The left side of the board viewed from Gold's perspective, specifically the a-, b-, and c-files.


A situation in which one player threatens goal and the other player can only prevent goal by moving a piece where it can be captured.

Sample Games · Resources

Sample Games · Arimaa · Resources