Fifteen rules

Start

Fifteen is played with 9 stones numbered 1 to 9, on a board consisting of 3x3 squares. The goal of Fifteen is to place 15 in a full line (horizontally, vertically, diagonally).

Course

Taking turns, the players pick one of the available stones and place it on an empty square.

End

The game ends when the sum of 3 adjacent stones (horizontally, vertically or diagonally) is exactly 15. The first player to do this wins the game.