Mills is played with 9 white and 9 black stones, on a board consisting of 3 squares with 8 dots each. The goal of Mills is to ensure that the opponent has less than 3 stones left or is unable to make any more moves.
The game is played in 2 phases. In the first phase, the players take turns placing one of their stones on a free dot on the board. As soon as a connecting line with 3 of their own stones has been formed -the so-called mill- the player may remove a stone from the opponent from the board. If possible, stones that are not in a mill must be removed first.
Once all 18 stones have been placed, the 2nd phase begins. Taking turns, the players move one of their own stones to an adjacent dot. When a mill is formed, the player may take another opponent's stone from the board. If a mill is broken, it may be re-formed on the next turn in the same setup. If a player has only 3 stones left, his stones may be moved to any free dot.
The game ends when one of the players has less than 3 stones left or is unable to move any of his stones. The other player wins the game. If both players only have 3 stones left or the same layout occurs 3 times, the game ends in a draw.