Board: 8×8 grid (64 squares), files a–h, ranks 1–8.

Pieces (per side): 1 King, 1 Queen, 2 Rooks, 2 Bishops, 2 Knights, 8 Pawns.

Movement: Standard chess rules apply. Includes castling, en passant, and pawn double-step on first move. Pawns promote on the 8th rank.

Win condition: Checkmate the opponent’s King. Draws by stalemate, threefold repetition, 50-move rule, or insufficient material.

Board: 5×5×5 cube (125 cells). Squares addressed by file (a–e), rank (1–5), and level (A–E). Example: c3C is the center.

Pieces (per side): 1 King, 1 Queen, 2 Rooks, 2 Bishops, 2 Unicorns, 2 Knights, 10 Pawns. White starts on levels A–B; Black on D–E; level C starts empty.

Special piece — Unicorn: Slides along triagonals (all three axes change simultaneously), giving 8 unique directions with no 2D analogue.

Movement: Rook slides along 1 axis (6 directions). Bishop slides along 2 axes (12 directions). Queen combines Rook + Bishop + Unicorn (26 directions). Knight leaps 2+1 in 3D. King moves 1 square in any of 26 directions. Pawns advance by rank or level and capture diagonally forward.

Win condition: Checkmate. No castling, en passant, or double-step pawns.

Board: 5×5×5 cube (125 cells) with all three axes wrapping cyclically (3-torus topology). There are no edges, faces, or corners.

Pieces: Same as Raumschach (includes Unicorn).

Movement: All Raumschach piece movements apply, but sliding pieces wrap around all axis boundaries. Every position has identical connectivity.

Win condition: Checkmate. No castling.

Board: 5×5×6 grid (150 cells) with 3D projective topology. Crossing any face of the cube sends a piece to the antipodal point: the other two coordinates are flipped (reflected through the center).

Pieces: Same as Raumschach (includes Unicorn).

Movement: Raumschach moves with antipodal face-crossing. A rook sliding off rank 1 at position (x, z) re-enters at rank 5 at (4−x, 5−z). This creates a non-orientable 3D space.

Win condition: Checkmate. No castling.

Board: 8×8 grid with toroidal topology — both files and ranks wrap around. The a-file is adjacent to the h-file; rank 1 is adjacent to rank 8.

Pieces: Standard chess set.

Movement: All standard piece movements, but sliding pieces wrap across edges. A rook on a1 can slide left to h1, g1, etc. Every square has identical connectivity (no corners or edges).

Win condition: Checkmate. No castling. Uses a modified starting position to prevent instant checkmate.

Board: 8×8 grid with cylindrical topology — files wrap (a-file adjacent to h-file), ranks are bounded normally.

Pieces: Standard chess set.

Movement: Standard piece movements with horizontal wraparound. Rooks, bishops, and queens can slide across the a/h file seam. No castling.

Win condition: Checkmate.

Board: 8×8 grid with vertical cylindrical topology — ranks wrap (rank 1 adjacent to rank 8), files are bounded normally.

Pieces: Standard chess set.

Movement: Standard piece movements with vertical wraparound. Rooks can slide cyclically along the entire file. No castling.

Win condition: Checkmate.

Board: 7×8 grid with Möbius strip topology — a non-orientable surface. Files wrap with a rank-flip: sliding off file g re-enters at file a with rank y mapped to (7−y). Ranks are bounded.

Pieces: Standard chess set.

Movement: Standard piece movements obeying the file-flip wrap. A piece sliding right off the board reappears on the opposite side with its rank inverted. No castling.

Win condition: Checkmate.

Board: 7×8 grid with Klein bottle topology — a non-orientable surface. Files wrap normally (a↔g). Ranks wrap with file-flip: sliding off rank 8 re-enters at rank 1 with file x mapped to (6−x).

Pieces: Standard chess set.

Movement: Standard piece movements obeying both wraps. The combination of normal file-wrap and flip rank-wrap creates a Klein bottle. No castling.

Win condition: Checkmate.

Board: 7×8 grid with projective plane topology — a non-orientable surface. Files wrap with rank-flip AND ranks wrap with file-flip. Both seams are antipodal (reversed).

Pieces: Standard chess set.

Movement: Standard piece movements obeying both flip-wraps. There is no global “up” direction. No castling.

Win condition: Checkmate.

Board: Two standard 8×8 boards (Board A and Board B), 128 squares total. All pieces begin on Board A; Board B starts empty.

Pieces: Standard chess set.

Special rule — Teleportation: After every move, the moved piece teleports to the same square on the other board. A move is only legal if the destination square on the receiving board is vacant. Check is evaluated across both boards simultaneously.

Win condition: Checkmate. Every move has a dual effect — the immediate tactical consequence and the teleportation consequence on the other board.

Board: Five independent 8×8 boards played simultaneously, with point values: 1, 2, 3 (center), 2, 1.

Pieces: Standard chess set on each board.

Special rule: Each turn, a player selects one of the five boards and makes a single move on it. Boards resolve independently upon checkmate or stalemate.

Win condition: Accumulate the majority of points. The center board is worth 3 points, making it the most valuable strategic target.

Board: 8×8 grid. No pawns.

Pieces (per side): 1 King, 1 Queen, 2 Rooks, 2 Bishops, 2 Knights. All pieces start packed on ranks 1–2.

Special rule: Check is illegal — no move may place any king in check. There is no checkmate.

Win condition: The first player to move their King to rank 8 wins. If White reaches rank 8, Black gets one more turn to reach rank 8 as well (resulting in a draw).

Board: 8×8 grid.

Pieces: Standard chess set, plus a reserve (hand) of captured pieces.

Special rule — Drops: Captured pieces switch color and enter your reserve. Instead of moving a piece, you may drop a reserve piece onto any empty square. Pawns cannot be dropped on ranks 1 or 8. Promoted pawns re-enter the reserve as pawns.

Win condition: Checkmate. Material advantage is diminished since captured pieces return to play.

Board: 8×8 grid.

Pieces: Standard chess set.

Special rule: There is no check or checkmate concept. All pseudo-legal moves are allowed, including moving into “check.” Castling is permitted even through attacked squares.

Win condition: Capture the enemy King. The game ends immediately when a king is taken.

Board: 8×8 grid.

Pieces: Standard chess set.

Special rule: In traditional Kriegspiel, players cannot see each other’s pieces — a referee announces limited information (e.g., “check” or “capture on square X”). The underlying rules are identical to standard chess.

Win condition: Checkmate, as in standard chess.

Board: 91 hexagonal cells arranged in a hexagon shape. 11 files (a–l, skipping j), ranks 1–11. Three cell colors.

Pieces (per side): 1 King, 1 Queen, 2 Rooks, 3 Bishops (one per hex color), 2 Knights, 9 Pawns.

Movement: Rooks slide along 6 edge-adjacent directions. Bishops slide along 6 color-preserving diagonals. Queen combines Rook + Bishop (12 directions). Knights leap to 12 destinations at distance √7. Pawns move forward along one axis and capture diagonally forward.

Win condition: Checkmate. No castling or en passant.

Board: 96 triangular cells arranged in a hexagonal pattern with 8 cells per edge. Cells alternate between pointing up and down.

Pieces (per side): 1 King, 1 Queen, 2 Rooks, 2 Bishops, 2 Knights, 1 Unicorn, 11 Pawns.

Movement: Rooks move through cell edges. Bishops move through cell vertices (limited range). Queen combines both. The Unicorn makes an extended knight leap: 2 rook-steps + 1 orthogonal rook-step.

Win condition: Checkmate. No castling or en passant.

Board: 61 cells in a diamond (cross) shape. 9 files (a–i), with row widths of 5, 6, 7, 8, 9, 8, 7, 6, 5.

Pieces (per side): 1 King, 1 Queen, 3 Rooks, 3 Knights, 2 Bishops, 9 Pawns (19 total). The enlarged piece set reflects the larger board.

Movement: Standard piece moves on the irregular board. Pawns advance one step forward only (no double-step, no en passant). Promotion rank varies by file. Kingside castling only.

Win condition: Checkmate.