Crab Canon
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English is the default. Your choice applies to all games and lessons.

Möbius shogi

Save position

Download a position file, or copy its text into a .json file.

The three surfaces

The flat charts show squares on a connected surface. Highlighted connections show where a move continues.

Möbius
A 9 × 11 board. The side edges join with a reflection; top and bottom remain boundaries.
Klein
A 9 × 18 board, displayed in two halves. The side edges reflect, and ranks 18 and 1 also connect.
Genus 2
One surface represented by two 9 × 9 charts. Marked connections carry moves between and within the charts.

Black and White identify the players. The pointed end of a piece shows its current forward direction. Ownership does not change when facing changes.

Play takes turns. Analyze lets you move either side. Edit changes the analysis position freely.

Use arrow keys to move focus through the surface's actual joins, Enter to select, and Page Up or Page Down to switch panels. Escape clears a selection. Ctrl/Command Z steps back through moves.