Crosso is played on a square grid at least 5x5 in size. Players take turns entering their symbols (e.g. X and O) in empty spaces. If the grid side is an odd number then one space will be left empty so each player has the same number of turns. The starting player is called the attacker and is the only one who scores; they score for each row, column, or major diagonal with at least three of the same symbol together, regardless of whose symbol it is. The more symbols the more they score. Since only one player scores the game needs to be played an even number of times, reversing positions each time.