Ko shogi

Ko shogi, whose name translates roughly as broad chess, is a large-board variant of shogi, the Japanese form of chess, and also draws on ideas from xiangqi and go. The game dates to around the turn of the eighteenth century and is credited to the Confucian scholar Ogyu Sorai, who lived from 1666 to 1728 and recorded its rules in his book Koshogifu. It is played by two players on a very large board of nineteen by nineteen intersections, the same grid size used for go, which is far larger than the boards used for standard shogi or chess. As an abstract strategy game rooted in the historical shogi family, ko shogi represents one of the most elaborate large-board chess variants developed in premodern Japan, reflecting the era's scholarly interest in expanding and reworking traditional board games.