The Three Knights Game is a chess opening which most commonly begins with the moves: In the Three Knights Game, Black chooses to break symmetry in order to avoid the main lines of what is often considered the drawish Four Knights Game after the usual 3...Nf6.

After tries such as 3...d6 or 3...Be7, White can play 4.d4, leaving Black with a cramped position resembling Philidor's Defense.

Since tournament praxis shows the line seems to favor White, Black usually plays 3...Bb4 or 3...g6, the Steinitz Defense.

Then 4.Bb5 transposes into the Schliemann Defense of the Ruy Lopez.

The similar position with Black having moved ...Nf6 is called Petrov's Three Knights Game, although it too usually leads to the Four Knights Game.