Choose your table
Two players share a classic square. Add an army and the board opens into a radial arena, up to six players and 192 squares.
Two to six players · One shared table
Chess beyond
two players.
A familiar opening. An unfamiliar frontier. Bring more armies to the board, command your corner, and see where the game takes you.
Local play, human versus AI, or an all-AI match.
No account needed. Human players share this device.
The board grows.
The possibilities follow.
Start with classic chess, or explore the boundaries between sectors.
Meet at the seams
Rooks cross into neighboring sectors. Diagonals can branch through the center. Your next move may come from an unexpected direction.
Conquer a new army
In multiplayer conquest, defeating a king brings its remaining pieces under your command. Switch it off for conventional elimination.
Before the first move
Set the table.
Gold to move
Select a piece to see its legal moves.
Arrow keys navigate · Enter selects or moves · Escape clears
Active armies
By win estimatePosition-based estimates, not calibrated probabilities. Draws are not predicted.
Move history
Ply 0
Checks, conquests, and eliminations appear here alongside moves.
A familiar game, with a few new paths
A guide to the board.
Dots show where the rook can move across a seam.
Two players: classic chess
Gold moves first. Pawns move toward the opposing army, capture diagonally, and may advance two squares on their first move. The standard rules for check, castling, en passant, and promotion apply. A king is checkmated, never captured.
Stalemate is a draw. This game automatically draws on threefold repetition or 50 full moves without a pawn move or capture. It also detects common insufficient-material positions. These are casual automatic rules, not complete tournament adjudication or detection of every possible dead position.
Three to six: across the sectors
On radial boards, each additional army adds 32 squares. Left-wing files cross into the clockwise neighbor; right-wing files cross counter-clockwise. Rooks follow those seams. Diagonals at the central vertex can branch into opposing sectors. Select a piece to see the available destinations.
Pawns advance toward the center in their owner's sector, then away from it in other sectors. A pawn reaching another sector's back rank promotes. Conquered pawns follow their new owner's direction.
The optional three-arm trial has 144 cells and keeps sector movement. The four-player Cross board has 192 square cells: four 8 × 4 arms around an 8 × 8 center. On Cross, rooks and bishops follow straight grid lines, knights jump in an L, and pawns keep advancing toward the opposite outer back rank, where they promote. Captures remain diagonal; conquered pawns follow the new owner's forward direction.
Conquest and elimination
With conquest enabled, capturing or checkmating a king converts its remaining non-king pieces to the conqueror. If multiple armies threaten the king, the most recent mover is credited when it is an attacker; otherwise the first attacking army in board order receives the conquest.
Without conquest, eliminated armies freeze as uncapturable obstacles or are removed, according to your settings. Stalemate eliminates an army in multiplayer. First-checkmate mode ends the match immediately when a king is checkmated or captured.
Donut and Möbius
Donut: this 64-cell annular experiment joins files a/h at the same rank. Gold starts inside, Crimson outside. Ranks 1/8 remain boundaries, so this is cylindrical movement rather than a torus.
Möbius: based on Alberto Monteiro’s Chess in a Moebius Strip. The unfolded board has 8 files, 14 ranks and 24 pieces per army. Gold’s back rank is 1, with pawns on 2 advancing upward and 14 downward. Crimson’s back rank is 8, with pawns on 7 advancing downward and 9 upward.
Rank 14 connects to 1 without a twist. Crossing 11/12 reverses files: a11 joins h12, b11 joins g12. Continuing diagonals reverse their file direction; pawns keep their rank direction. The a/h sides are boundaries. A bishop can cross onto the other square color. Gold promotes on rank 8; Crimson on rank 1.
Castling stays on each home rank and en passant is supported. Rays stop at blockers and cannot circle back to their starting cell. OmniChess adds its casual draw policy: stalemate, threefold repetition, 100 half-moves or king versus king. Classic bishop/knight material shortcuts are not assumed. Earlier 8×8 Möbius saves retain their original experimental rules.
Five and six arms
In Setup, choose Five-arm for five players or Six-arm for six players. Each rectangular home arm has 8 files and 4 ranks. A pentagonal or hexagonal field adds 16 playable center cells per army: 240 cells for Five-arm, 288 for Six-arm.
These boards use sector movement, including seam crossings and branching diagonals. Pawns advance inward in their own sector, then outward in opposing sectors, promoting at an opposing back rank. Pieces keep the same size when moving into the center. The extra cells make routes longer than on the radial boards.
Reading the estimates
Winning prospects compare material, available movement, center control, pawn progress, threatened pieces, and king safety. Percentages total 100% across active armies, and the list is ranked highest first. These are heuristic estimates, not measured probabilities. A drawn match displays Draw.
Pausing, undoing, and saving
Settings and this guide suspend AI, restoring its prior pause state when you return directly to the match. Human-mode Undo returns to the latest human decision, removing subsequent AI replies. Spectator Undo removes one move and stays paused. Undo keeps current controllers and settings; multiplayer rule changes remain in effect.
Matches are saved in this browser when storage is available. Returning from Home or Setup, or restoring a save, pauses AI. Human turns can still be played while AI is paused. Saves do not follow you between devices, browsers, or preview and production addresses.