Arimaa/Lone Elephant Attacks
A Lone Elephant Attack occurs when the elephant advances while the rest of the army stays behind. Extended lone elephant attacks are now rare, but may work if the opponent isn't good at multi-piece trap attacks.
Reasons to use the Lone Elephant Attack
By pulling rabbits, the gold elephant has disrupted Silver's trap defense. (Game)
- to push and pull enemy pieces toward one's home traps for potential capture
- to disrupt the enemy defensive position
- to threaten capture in a poorly defended away trap, perhaps during a race
At right, the gold elephant has pulled two silver rabbits to the sixth rank. Unable to retreat homeward, these rabbits are vulnerable to eventual capture in f3, but Gold might leave them in place and first go after the silver camel or horse, which currently have limited escape paths. If the silver camel flees west, the eastern gold horse might safely advance, turning a lone elephant attack into something more. Seeing his vulnerabilities, Silver might consider swarming the southeast trap and thus taking a space advantage in the east.
Risks Involved with the Lone Elephant Attack
- Advancing an elephant beyond the 6th rank, or into a corner, may expose it to a blockade.
- If the elephant wanders too far from its home traps, they may become increasingly vulnerable to a multi-piece attack.
- Enemy rabbits dragged homeward, but not captured, may later become goal threats.
- One who keeps nearly all friendly pieces at home could become cramped if the opponent plays aggressively.
Defense and Counter-Attacks
When the enemy elephant pulls non-rabbit pieces, there are defensive and counter-attacking options:
- use friendly pieces, especially the elephant, to help pulled pieces retreat
- respond in kind, pulling enemy pieces homeward
- launch a multi-piece trap attack, which might make it hard for the opponent to continue with lone elephant play
When the opponent pulls rabbits, the options are similar, but narrower. Since rabbits can't retreat homeward, it is urgent to counterattack somehow.
Dual Lone Elephant games
Dual Lone Elephant game after 9s.
A Dual Lone Elephant game occurs when neither player actively uses any piece other than his elephant. This was a Dual Lone Elephant game until 14s, when Silver advanced a horse. Although neither side took advantage of this, the d- and e-file rabbits were vulnerable here. Since a rabbit can only step sideways or forward, a rabbit pull in the center will disrupt a home-oriented game.
Unlike Gold, Silver has placed all eight rabbits on her home rank. From here, Silver should not attempt a Lone Elephant Attack, as her own d8 and e8 rabbits are vulnerable.
To prevent central rabbit pulls, Arimaa players often use a 99of9 setup and move a rabbit to the d- or e-file only when a central goal must be blocked. Any other piece pulled in the center can retreat, and a rabbit pull on a flank would be riskier and less beneficial for the opponent. One who intends to begin with a Lone Elephant Attack should leave his own rabbits off the d- and e-files initially, so as not to fall behind in a potential Dual Lone Elephant game.
If players shield their rabbits and retreat pulled pieces, a Dual Lone Elephant opening might go on and on without capture. In other cases, players might simply pull pieces on opposite wings and gradually decimate each other's armies. Either way, deviation from lone elephant play will be key to the outcome. One might advance non-elephant pieces into weakly defended territory, setting up a trap attack or goal attack.
This Dual Lone Elephant game featured sweeps beneath the traps, rabbit pulls along the perimeter, and threats to push stronger pieces into the center. Gold outdid Silver, capturing five rabbits while losing only one rabbit himself in the first 51 turns. Had Silver played differently, however, Gold would not have had time for such methodical play.