Minishogi
Minishogi was invented (or rediscovered) around 1970 by Shigenobu Kusumoto of Osaka, Japan. It applies Standard Shogi rules to a 5×5 board, reducing each player’s force to five pieces and the promotion zone to the single back rank. Game mechanics are not copyrightable; the rules have been freely published for over 50 years.
Minishogi — starting position
https://engine.moddable.games/play/?game=shogi&variant=minishogi
Setup
Board: 5×5 grid, 25 squares.
Pieces per player: 6 (King, Rook, Bishop, Gold General, Silver General, one Pawn). No Knights or Lances: the board is too small for their jump.
Starting position:
| Player | Rank | Pieces (files 5–1, left to right) |
|---|---|---|
| White (top) | Rank 5 | Rook · Bishop · Silver · Gold · King |
| White | Rank 4 | Pawn at file 1 only |
| Black (bottom) | Rank 1 | King · Gold · Silver · Bishop · Rook |
| Black | Rank 2 | Pawn at file 5 only |
Pieces
| Piece | Movement |
|---|---|
| King | One square in any direction. Cannot move into check. |
| Rook | Any number of squares orthogonally. |
| Bishop | Any number of squares diagonally. |
| Gold General | One step orthogonally or diagonally forward. Six directions. |
| Silver General | One step diagonally, or one step forward. Five directions. |
| Pawn | One step directly forward. |
Promotion
The promotion zone is the final rank only (rank 5 for Black, rank 1 for White). A piece may promote when it moves into or within the promotion zone. Promotion is mandatory when the Pawn reaches the final rank with no other legal move.
Promoted pieces:
| Base piece | Movement when promoted |
|---|---|
| Rook | Dragon King: Rook moves plus one square diagonally |
| Bishop | Dragon Horse: Bishop moves plus one square orthogonally |
| Silver General | Moves as Gold General |
| Pawn | Tokin: moves as Gold General |
Kings and Gold Generals do not promote.
Drops
The drop mechanic applies as in Standard Shogi. Captured pieces are held in hand and may be dropped onto any empty square on a later turn, unpromoted. Restrictions: no Pawn drop on a file already containing a friendly unpromoted Pawn; no Pawn drop for immediate checkmate; no drop where the piece would have no legal move.
Win Condition
Checkmate the opponent’s King. A player with no legal moves loses.
Draws
Sennichite: The same position (including pieces in hand) occurs four times with the same player to move. Draw. If caused by perpetual check, the checking side loses.
Impasse: Both Kings enter the promotion zone and neither can be mated. Count material: Rooks and Bishops score 5 points each; all others score 1 point each. A player with fewer than 24 points loses. If both reach 24 or more, the game is a draw.
Attribution
Minishogi. Invented (or rediscovered) c. 1970 by Shigenobu Kusumoto of Osaka. Rules freely published since then; game mechanics are not copyrightable. Sources: pychess.org/variants/minishogi; Fairy-Stockfish variants.ini engine definition.