Place your disc to outflank your opponent's discs (trap them between your pieces). All outflanked discs flip to your color. The player with the most discs when the board is full (or no moves remain) wins.
If you have no valid moves, your turn is automatically passed to your opponent. If neither player can move, the game ends.
The game starts with 4 discs in the center: 2 black and 2 white in a diagonal pattern.