X-O is played on a board showing 129 yellow/orange/red squares where numbers between 1 and 25 can be read.
Each player rolls 3 dice to obtain a number or numbers similar to the one(s) on the square where the player wishes to place one or several of his tokens. For example, a player rolls 3/4/6 : a) he may place 3 tokens on squares "3", "4" and "6" ; b) he may place 2 tokens on square "12" (=3x4) and "6" ; c) he may place 1 token on square "18" (=3x4+6). All operations may be used.
When a player places 5 of his tokens in a straight line orthogonally or diagonally, he scores points according to the colour of the squares they are located on : 1 point on a yellow square, 2 points on an orange square, 3 points on a red square.
The game ends when a player runs out of tokens. Each unplayed token is worth 1 point for each player. The player with the maximum score wins.
—user summary
A winner of the 1987 Concours International de Créateurs de Jeux de Société.