Arimaa/Initial Piece Placement

From Wikibooks, open books for an open world
Jump to: navigation, search

Previously, it was suggested that beginners use a balanced setup which shields Rabbits. That setup is also popular among expert players, especially for Gold, but unbalanced setups can work better if you like to start out aggressively. It is probably best to use a balanced setup until you understand the advantage in an unbalanced setup.

37px-Arimaa board.jpg
a8 b8 c8 d8 e8 f8 g8 h8
a7 b7 c7 d7 e7 f7 g7 h7
a6 b6 c6 d6 e6 f6 g6 h6
a5 b5 c5 d5 e5 f5 g5 h5
a4 b4 c4 d4 e4 f4 g4 h4
a3 b3 c3 d3 e3 f3 g3 h3
a2 b2 c2 d2 e2 f2 g2 h2
a1 b1 c1 d1 e1 f1 g1 h1
Gold intends an Elephant-Horse attack on f6; Silver has prepared to blunt it.

In the diagram at left, Gold has chosen a rather more aggressive setup. The Elephant is placed to immediately attack the f6 trap in conjunction with a Horse coming up the g-file. The Camel, meanwhile, intends a secondary attack on the c6 trap, on the theory that the Silver Elephant will be tied up by the primary attack. The pressure exerted by the Gold Camel will make it difficult for Silver to keep a piece on b6, most particularly a Horse.

Gold might as well start with several Rabbits forward, too. Advanced Rabbits are necessary to support an advanced Camel, and they can increase the threat posed by an Elephant-Horse attack. Moreover, if Gold manages to share control of both c6 and f6, any advanced Gold Rabbits are in no immediate danger of capture.

Silver, in response, has allocated both Elephant and Camel to the defense of f6, hoping to take Gold's Horse hostage if it advances. All of the Silver Rabbits are placed on the back row where they are not vulnerable to attack. Silver needn't fear that Gold will launch a lone-Elephant attack up the middle to pull the d8 and e8 Rabbits, because the vulnerability of Gold's Camel ensures Silver the upper hand in any Rabbit-pulling opening. (Gold will have to voluntarily advance Rabbits to keep the Gold Camel safe.) Silver supposes that Gold must attack given Gold's aggressive setup, so Silver is mostly concerned to make any Elephant-Horse attack on f6 costly for the invading Horse.

Early Arimaa theory advocated placing all eight Rabbits on the back row for both sides in every setup, but the average number of Rabbits placed forward has been creeping upward as it becomes clear that advanced Rabbits have positional value to offset their vulnerability to capture. As of October 2005, the initial setups on the Arimaa server averaged about one and a half Rabbits in the front row.


To do:
1. Link to appropriate resource.
2. Update to more recent data.

Most players will split their Horses, Dogs, and Cats to have one on each side of the board, in keeping with the principle that balanced forces are most effective. However, as top players experiment with setups including a decentralized Elephant and/or decentralized Camel, it seems occasionally advantageous to place both Horses on the same wing, near the Elephant and far from the Camel.

Relative Value of Pieces · Advanced Tactics