On a player’s turn, the active player must perform one of the following two actions:
1. Distribute a stack of two owned pieces onto the two nearest squares in any one orthogonal or diagonal direction. Each destination square must be empty or contain a single owned piece (singleton). This implies that distribution is blocked by the edge of the game board, the presence of an opponent piece, or any stack, including owned stacks! Note that the distribution onto owned singletons creates new stacks. Stack size is limited to two. Stacks never consist of opposing pieces.
2. Sacrifice a piece from an owned stack to remove any one orthogonally or diagonally adjacent opponent singleton from the board. Sacrifice cannot be used to reduce opponent stacks to singletons. Sacrifice is not forced by the mere presence of an opponent’s singleton.
If at the start of a turn, a player cannot perform either action, the player is stalemated.
A player wins by
- breakthrough, distributing a piece in the opponent’s home row , or
- stalemate, leaving the opponent with no moves or sacrifices.