Players & Turn Order

4 players: White (bottom), Blue (left), Green (top), Red (right). Turn order: White → Blue → Green → Red, repeating.

Shared Pieces

Corner pieces are shared between two adjacent players — shown as half-half coloured.

• From starting square: only the edge-owner can move it first (corner intersections — either owner)
• Once moved: both owners can move it freely on their turns
• Shared pieces cannot check, capture, or be captured by any King
• Shared pieces can block a check on a King

Capture Rule

A piece cannot capture any piece that shares at least one colour with it.

Check & Checkmate

A player in check deals with it on their own turn — no players are skipped. Only solo pieces can check or checkmate a King.

Stalemate

A stalemated player stays in the game. Turn passes until a legal move becomes available.

Elimination

When a King is checkmated, solo pieces are removed. Shared pieces transfer to the surviving co-owner.

Pawn Movement

Each owner moves a shared pawn in their own forward direction. First move may be 2 squares. No en passant.

Castling

Standard castling for all 4 players. Shared Rooks remain shared. Either co-owner can castle with a shared Rook.

Pawn Promotion

Corner squares (a1, h1, a8, h8) give shared pieces. All others give solo pieces. Mover chooses piece type.

Win Condition

Last King standing wins. Two Kings with no other pieces = draw.