Arimaa/Initial Piece Placement
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.
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.
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.