Sho Shogi

Sho Shogi

Shō Shogi (小将棋, “small chess”) is a 16th-century form of Shogi and the immediate predecessor of the modern game. It is played on a standard 9×9 board with the same starting position as modern Shogi, with one addition: each side has a Drunken Elephant placed directly in front of the King. According to the Sho Shogi Zushiki, the Drunken Elephant was eliminated by Emperor Go-Nara (reigned 1526–1557), and the drop rule is believed to have been introduced at roughly the same time, giving rise to modern Shogi.

Setup

Board: Standard 9×9 grid.

Pieces per player: 21 — all standard Shogi pieces plus one Drunken Elephant.

Starting position: Identical to Standard Shogi, except each side has a Drunken Elephant (E) on the square directly in front of the King.

Sente (Black) moves first.

SFEN: lnsgkgsnl/1r2e2b1/ppppppppp/9/9/9/PPPPPPPPP/1B2E2R1/LNSGKGSNL[-] b - 1

(E/e = Drunken Elephant; all other letters match standard Shogi notation.)

Pieces

All standard Shogi pieces move as normal. The Drunken Elephant is the sole addition:

Drunken Elephant (E): Moves one square in any of the eight directions except directly backward. It cannot step to the square immediately behind it (seven legal directions total). Promotes to the Crown Prince on reaching the promotion zone.

Crown Prince (CP): Moves one square in any direction (like a King). The Crown Prince is also a royal piece — if both the King and Crown Prince are on the board, both must be captured or checkmated for that player to lose. A side with a Crown Prince on the board cannot be defeated by checkmate of the King alone.

Rules

All standard Shogi rules apply, with these exceptions:

No drops. Captured pieces are removed from play and do not return to the board.

Dual royalty. A side that has promoted its Drunken Elephant to Crown Prince requires both the King and Crown Prince to be neutralised before that side loses.

Promotion

The promotion zone is the three ranks farthest from each player (ranks 7–9 for Sente). Standard Shogi pieces promote as normal. The Drunken Elephant promotes to Crown Prince; the Crown Prince does not promote further.

Win Conditions

Checkmate: The sole remaining royal piece is in check with no legal escape. If only a King remains (no Crown Prince), standard checkmate applies. If a Crown Prince remains alongside the King, both must be simultaneously without legal escape.

Attribution

Sho Shogi is a historical game, public domain. Rules documented from pychess.org/variants/shoshogi and H.J.R. Murray, A History of Chess (Oxford University Press, 1913).