Sankaku Shogi

Sankaku Shogi

Sankaku Shogi (三角将棋, “Triangle Shogi”) is a modern Shogi-inspired variant designed by L. Lynn Smith in 2004. It is played on a field of 44 triangular cells. Each player controls 13 pieces. Unlike standard Shogi, captured pieces are permanently removed from play — there are no drops.

Board

The playing field consists of 44 triangular cells in a diamond pattern with the four extreme corners removed to reduce choke points. Files are labeled a–g; ranks 1–8. The field is narrowest at ranks 1 and 8 (2 cells wide) and widest at ranks 4 and 5 (4 cells wide).

Orthogonal movement is through shared sides (each step from one cell to the next sharing a complete side). Adjacent movement includes cells connected by either side or point — giving each interior cell up to 5 neighbours.

Starting Position

Black:

• Emperor: d1
• Chariots: c1, e1
• Cavalry: b2, c2, e2, f2
• General: d2
• Soldiers: b3, c3, d3, e3, f3

White:

• Emperor: d8
• Chariots: c8, e8
• Cavalry: b7, c7, e7, f7
• General: d7
• Soldiers: b6, c6, d6, e6, f6

Pieces

Emperor: Leaps to any cell on the entire board. Cannot capture an opponent Emperor that is defended (any opponent piece could recapture on that square).

Chariot: Slides orthogonally any number of cells. Cannot be captured by Soldiers. Can “run down” a Soldier: captures the Soldier and continues sliding to end on a vacant cell or capture another piece.

General: Steps to any adjacent cell (connected by side or point — up to 5 cells).

Cavalry: Leaps to the second orthogonal cell. If that cell is occupied by a friendly piece, the Cavalry makes one additional leap in any direction (not returning to start). The second leap must land on a vacant or enemy-occupied cell.

Soldier: Steps one orthogonal. May capture on the second orthogonal cell if the first orthogonal cell is vacant. Cannot capture Chariots. Mandatorily promotes to General upon making any capture.

Promotion

Soldiers and Cavalry promote to General immediately and mandatorily upon making any capture. There is no optional promotion and no promotion zone. Generals, Emperors, and Chariots do not promote.

Rules

• Black moves first.
• Each player must move every turn — passing is not allowed.
• All captured pieces are permanently removed (no drops, no recycling).
• Win: Capture the opponent’s Emperor.
• Repetition: A player may not repeat a position solely to avoid capture.

Attribution

Designed by L. Lynn Smith, 2004. Rules documented from chessvariants.com/44.dir/sankaku-shogi.html.