The following rules apply to official Arimaa games that are played for ranks, tournaments, contests, championships, etc.
Match Game Requirements
Players may not offer a draw. An official Arimaa match is to be considered similar to a real sporting event. As such the players may not agree to end the match in a draw. The intention of an Arimaa match is to determine a winner. So when 2 players enter into a match they are not allowed to mutually end the match as a draw.
One of the players may resign at any time to end the match, although resigning is highly discouraged. Continuing a game to a natural finish is highly encouraged.
Time controls must be used. An official Arimaa match must be played with some form of Arimaa Time Control. Details of time controls are given below.
If a game must be stopped after a fixed amount of time then the Arimaa Scoring System must be used. After the preset time limit for the game expires, but the game has not finished the winner is determined by score. Details of the Arimaa Scoring System are given below.
Before the start of the game, it must be decided if the game will be allowed to end in a draw or not. Details for breaking draws are given below.
Game must be recorded. All moves made in the game must be recorded using the Notation for Recording Arimaa Games
Scoring System
If the amount of time which was set for the game runs out, then the following scoring system is used to determine a winner. The player with the higher score wins the game. In case the score of both players is the same, the game is a draw.
Score for each player is determined as follows:
Score = R + P*(C+1) R = Points given for how far the players Rabbits have progressed. The row to which each rabbit has progressed is cubed (i.e. raised to the power of 3) and these values are summed up to determine R. The first row is 1 and the goal row is 8. C = The number of Rabbits the player still has on the board. P = Points given for the pieces the player still has on the board. The value of each piece on the board is summed. Value of each piece is: 1 - Rabbit 2 - Cat 3 - Dog 4 - Horse 5 - Camel 6 - ElephantTime Controls
The Arimaa time controls were chosen to achieve the following: 1. Keep the game moving, by not allowing a player to take forever to make a move and bore the spectators. 2. Allow a lot of flexibility in specifying the time controls. 3. Allow for a fixed upper limit on the total game time for practical reasons. 4. Attempt to prevent a player from losing the game due to time while imposing these time limits. 5. Preserve the quality of the game while imposing these time limits. 6. Allow for the most common time controls used in Chess. Thus the Arimaa time controls support all the common time controls used in Chess and more. The time control used for Arimaa is specified as: M/R/P/L/G/T where M is the number of minutes:seconds per move R is the number of minutes:seconds in reserve P is the percent of unused move time that gets added to the reserve L is the number of minutes:seconds to limit the reserve G is the number of hours:minutes after which time the game is halted and the winner is determined by score. G can also be specified as the maximum number of moves. T is the number of minutes:seconds within which a player must make the move On each turn a player gets a fixed amount of time per move (M) and there may be some amount of time left in the reserve (R). If a player does not complete the move within the move time (M) then the time in reserve (R) is used. If there is no more time remaining in reserve and the player has not completed the move then the player automatically loses. Even if there is time left in the move or reserve, but the player has not made the move within the maximum time allowed for moves (T) then the player automatically loses. If a player completes the move in less than the time allowed for the move (M), then a percentage (P) of the remaining time is added to the players reserve. The result is rounded to the nearest second. This parameter is optional and if not specified, it is assumed to be 100%. An upper limit (L) can be given for the reserve so that the reserve does not exceed L when more time is added to the reserve. If the initial reserve already exceeds this limit then more time is not added to the reserve until it falls below this limit. The upper limit for the reserve is optional and if not given or set to 0 then it implies that there is no limit on how much time can be added to the reserve. For practical reasons a total game time (G) may be set. If the game is not finished within this allotted time then the game is halted and the winner is determined by scoring the game. This parameter is optional and if not given (or set to 0) it means there is no limit on the game time. Also instead of an upper limit for the total game time, an upper limit for the total number of turns each player can make may be specified. After both players have taken this many turns and the game is not finished the winner is determined by scoring the game. For games which use a time per move of less than 1 minute, both players are always given 1 minute of time to setup the initial position in the first move of the game. If the setup is not completed in 1 minute then the reserve time (R) is also used. The unused time from the setup move is not added to the reserve time unless the player completes the setup in less time than the time per move (M) set for the game. If so then a percentage (P) of the unused time after deducting the time used from the time per move set for the game is add to the reserve time. Example 1: 0/5 means 0 minutes per move with 5 minutes in reserve (per player). This is equivalent to G/5 in Chess; it means each player has a total of 5 minutes of time to play. If a player runs out of time before the game is over, the player loses. This is known as Blitz or "Sudden Death" time control in Chess. Example 2: 0:12/5 means 12 seconds per move with 5 minutes in reserve and all of the unused time from each move is added to the reserve time. It is similar to "5 12" in Chess which means "Game in 5 minutes with a 12 second increment". After each move 12 seconds is added to the remaining time. This is known as Incremental time control in Chess. Example 3: 3/0 means 3 minute per move and no reserve time, but 100 percent of the unused time for each move is added to the reserve. This guarantees that each player will make at least 40 moves in 2 hours. This is similar to the "40/2" Quota System time control used in Chess. Example 4: 0:30/5/100/3 means 30 seconds per move with 5 minutes in reserve and 100% of the unused time from each move is added to the reserve time. When the reserve already exceeds the limit, more time is not added to it. When the reserve falls below 3 minutes more time can be added to it, but the reserve is capped at 3 minutes. Example 5: 4/2/50/10/6 This means 4 minutes per move with a starting reserve of 2 minutes. After the move 50% of the time remaining for the move (rounded to the nearest second) is added to the reserve such that it does not exceed 10 minutes. There is a limit of 6 hours for the game after which time the game is halted and the winner is determined by score. Example 6: 4/4/100/4/6 This means 4 minutes per move and a starting reserve of 4 minutess. 100% percent of the unused move time gets added to the reserve such that it does not exceed 4 minutes. There is a time limit of 6 hour for the game after which the winner is determined by score. Example 7: 4/4/100/4/90t This is the same as above, but the game ends after both players have made 90 moves. Thus it ends after move 90 of silver is completed. Example 8: 4/4/100/4/90t/5 This is the same as above, but the players may not take more than 5 minutes for each turn even if there is still time remaining in reserve. Different time units for any of the time control fields can be specifed by adding one of the following letters after the numbers. In such cases the letter serves as the seperator and : should not be used. s - seconds m - minutes h - hours d - days For example: 24h5m10s/0/0/0/60d means 24 hours, 5 minutes and 10 seconds per move and the game must end after 60 days. Such a time control may be used in a postal type match. The game time parameter (G) can also be specified in terms of maximum number of turns each player can make by adding the letter t after the number.Breaking Draws
In some tournaments it may be necessary to break draws or not allow them to occur in order to keep the tournament moving forward to maintain a fixed schedual. The rules of the tournament must clearly state that draws will be broken without additional games. In such cases the following additional rules are used: * Normally a game would continue when one of the players has lost all the rabbits and end in a draw if both players lose all the rabbits. However if draws are not allowed then a player may also win the game by being the first to capture all of the opponents rabbits. In the rare case where both players lose their last rabbit on the same move, the player making the move wins. * If the game is a draw due to the game time expiring and the the score being tied then the second player to setup the pieces at the start of the game wins.Notes
The rules for official matches are subject to change by the game desingers as more experience is gained with the game. These rules are effective April 1st, 2002.
You are free to copy and distribute these rules without any restictions or limitations. However, please be aware that the Arimaa game is covered under the Arimaa Public License