Hupo

Moves can only be made orthogonally (i.e. not diagonally).
Each move has three parts. The first must be played by the player with the stone designated by his opponent. The second part is with a stone determined by the player. This move may be omitted by the player and is not mandatory. The third part the player determines the stone to be moved by the opponent.

If the player is unable to move the stone designated by his opponent, that stone is removed from the board.

The player who manages to occupy his opponent's target square wins.