Sannin shogi

Sannin shōgi (三人将棋 three-person chess), or in full kokusai sannin shōgi (国際三人将棋 international three-person chess), is a three-person shogi variant invented circa 1930 by Tanigasaki Jisuke and recently revived. It is played on a hexagonal grid of border length 7 with 127 cells. Standard shogi pieces may be used, and the rules for capture, promotion, drops, etc. are mostly similar to standard shogi. (See that article for an explanation of these terms.) While piece movement differs somewhat from standard shogi, especially in the case of the powerful promoted king, the main difference in play is due to the rules for voluntary and mandatory alliance between two of the three players. Board and setup The board is thought to have originally been in the shape of an equilateral triangle bordered by three rectangles which contained the players' home territories and promotion zones. However, in terms of movement this was equivalent to a hexagon, and the modern form of sannin shogi is played on a hexagonal board, rather like the central portion of a Chinese checkers board. The three players occupy non-adjacent sides of the board; the three ranks nearest to them are their territories and their opponents' promotion zones. The 'international' arena inside the three territories remains triangular. The board is presented here with substitutions by standard shogi pieces; for the names actually used, see below.