Kō shōgi (広将棋 or 廣象棋 'broad chess') is a large-board variant of shogi, or Japanese chess. The game dates back to the turn of the 18th century and is based on xiangqi and go as well as shogi. Credit for its invention has been given to Confucian scholar Ogyū Sorai (1666–1728), who had also described the rules of the game in his book, Kōshōgifu (廣象棋譜).
Unlike standard shogi, pieces may not be dropped back into play after being captured. Promotion rules are complex, and the fates of several pieces...
