Sannin shogi

Sannin shogi, written in Japanese as three-person shogi and in full as kokusai sannin shogi, meaning international three-person shogi, is a variant of shogi for three players. It was invented around 1930 by Tanigasaki Jisuke and has been revived in recent years. The game is played on a hexagonal grid with a border length of seven, which gives 127 cells, and standard shogi pieces may be used. The rules for capture, promotion and dropping captured pieces are mostly similar to ordinary shogi, although piece movement differs somewhat, especially for the powerful promoted king. The main difference in play comes from the rules for alliances, because two of the three players may join forces either voluntarily or by compulsion, which turns the contest into a shifting three-sided struggle rather than a duel between two armies.