♟
♔ Game Rules
Rules
Learn how to play both variants of Circular Chess.
Board Overview
The board has 72 cells arranged in concentric circles. Each side has 16 pieces — identical to standard chess except for one Prince.
Notation
Cells are designated a–f on the left and g–l on the right. On the central vertical, light cells use a–f and dark cells use g–l.
Example — clockwise from d7: d7 d8 d9 i8 i7 i6 i5 i4 d5 d6
Every cell has neighbours across an edge (orthogonal) or a vertex (diagonal).
Special Cell Types
◆
Crescents
Cells aligned vertically through the centre. Same-colour crescent cells are vertex neighbours.
◑
Half Moons
The two central crescents with opposite colours. Each has 3 edge neighbours and 3 vertex neighbours.
⟺
Twin Cells
The two horizontal cells one edge away from a crescent or half moon.
Piece Movements
♔ King
1 cell in any direction. First move may leap 2 cells (even in check, even knight-style). Intermediate cell may be occupied but not threatened.
♙ Prince
Moves like a King but is not subject to check. On first move, may step 2 cells forward if it does not capture or leap.
♖ Rook
1 or more cells horizontally or around a circle. Cannot rotate a full 360° to its starting position. May move between g7 and f6 (and reverse).
♗ Bishop
1 or more cells diagonally, keeping its colour. Landing on a crescent or half-moon from a non-crescent enables a swing on the same move. Each bishop may change colour once.
♕ Queen
Combines Rook and Bishop movement.
♞ Knight
Crosses an edge then a non-adjacent vertex, or a vertex then a non-adjacent edge. Near twins or half-moons may move a short distance like a rook.
♟ Pawn
1 cell forward onto a different colour. May move 2 cells on its initial move. On a crescent or half-moon it becomes a Berolina pawn (moves diagonally, captures across an edge).
Pawn Movement Details
Regular Pawn
| Location | Move | Capture |
| Outer circle | Edge (1) | Diagonal (1) |
| Other cells | Edge (1) | Diagonal (2) |
Berolina Pawn (on crescent / half-moon)
| Location | Move | Capture |
| Home crescents | Diagonal (3) | Edge (2) |
| Home half-moon | Diagonal (2) | Edge (1) |
| Opp. half-moon | Diagonal (1) | Edge (2) side |
| Opp. crescents | Diagonal (1) | Edge (2) side |
Special Rules
Castling
Does not occur.
En Passant
As in standard chess.
Promotion
White promotes on row 10, Black on row 3. May become any piece except itself, the other pawn type, a Prince, or a King.
Prince Promotion
Like pawn promotion but may also become any standard piece — not itself, either pawn type, or King.
♙ All forward motion considers the opponent's vertex twins to the side as forward. ♟