A "battle" is a game between two players. With a send/receive system of challenges to connect the players, they compete on 10 randomly selected puzzles across the entire database. This selection is made considering the strength of the two players.
The two players do not need to be available on the site at the same time to play the "battle". They take turns and the end result will be displayed when the two players have completed the round.
A "battle" Elo is calculated following each "battle" by comparing the scores of the two players to decide if it is a win, defeat, or a draw.