The board begins empty. Both players have a set of 18 pieces. They are numbered 1 through 9 and they have two of each number. The game consists of two phases: deployment of forces and the claiming of territory.
 
In the first phase, Red begins and places any numbered piece anywhere on the board. The players then alternate until all the pieces are used up and the board is filled.
 
Since Blue moved second during the deployment phase, he moves first during the claiming phase. A player may claim any space occupied by an opponent's number as long as they have a number of equal or higher value orthogonally adjacent to it. A space is claimed by the planting of a Flag. Once a space is claimed with a Flag it may not be reclaimed by an opponent.
 
A player who has no move must pass. The other player can continue planting Flags as long as possible. The player with the most pieces on the board at the end of the game wins.