Microshogi is a Shogi variant played on a 4×5 board with hybrid pieces -- non-standard pairings of standard units: Bishop / Tokin Gold General / Rook Silver General / Lance Pawn / Knight King A piece is promoted (flipped) whenever it captures another piece. This is mandatory even when the flip side is a weaker unit. Also unlike 9×9 Shogi, captured pieces held in reserve can be dropped without restriction: A piece can be dropped with either side up. A piece can be dropped onto a rank that prohibits it from any further move. A pawn can be dropped onto the same column as another allied pawn. A pawn can be dropped to give immediate checkmate. Microshogi is believed to have been designed by Shogi Grand Master Yasuharu Oyama (1923-1992).