In the abstract strategy game MOD X, each player has 14 game pieces and 18 score markers, with the goal being to reach an established number of points (determined by the number of players). Players take turns placing a game piece on the board and trying to create scoring patterns – an "X", a "+", or a line, with each pattern requiring five pieces – while simultaneously trying to block their opponents from scoring with these same patterns.

After creating a successful pattern, a player places score markers on the board marking these spaces. Players can lose their score markers, however, if opponents create scoring patterns over these score markers on a later turn.

The game ends when one player reaches the established number of points (and wins) or a player runs out of pieces; in this latter case the player with the most points wins.