Osaka University of Commerce
is the largest known variant of shogi (Japanese chess). The game was created around the mid-16th century (presumably by priests) and is based on earlier large board shogi games. Before the rediscovery of taikyoku shogi in 1997, tai shogi was believed to be the largest playable chess variant ever. It has not been shown that taikyoku shogi was ever widely played. There are only two sets of restored taikyoku shogi pieces and one of them is held at Osaka University of Commerce. One game may be played over several long sessions and require each player to make over a thousand moves.