Each player has five double-sided cards of his own suit. On each of them, four different numbers are represented in squares (one in each corner). In the centre of the table are turned over and arranged in a square four cards on which only one number appears (there are nine cards in all, one for each number from 1 to 9).
When playing simultaneously, you must be the first to reproduce the four-digit pattern exactly, while placing four of your five cards to form a Sudoku grid: you must superimpose your cards to form a grid of only 3 squares by 3; the nine digits of the 3x3 grid thus obtained must all be different. We usually play in three winning rounds, but there is nothing to stop us from getting tired for longer.
