Heian dai shogi (Japanese: 平安大将棋 'Heian (Era) large chess') is an early large board variant of shogi (Japanese chess) as it was played in the Heian period. The same 12th century document which describes the Heian form of shogi also describes this variant.[1][2] Unfortunately, this description does not give enough information to actually play the game, but this has not stopped people from attempting to reconstruct this early form of shogi. A fairly complete and playable reconstruction is outlined here.