The Four Knights Opening

The Four Knights Game is a chess opening that begins with the moves:

1. e4 e5
2. Nf3 Nc6
3. Nc3 Nf6

This is the most common sequence, but the knights may develop in any order to reach the same position.
The opening is fairly popular with beginners who strictly adhere to the opening principle: “Develop knights before bishops.” It was one of the workhorses in the family of the Open Game, at even the highest levels, until World War I. Thereafter it fell by the wayside, along with a number of open games. In this period ambitious players explored the Ruy Lopez, believing it a better attempt for White to exploit the advantage of the first move. In the 1990s, this opening saw a renaissance, and is now seen in the praxis of players from beginner to Grandmaster.
The Four Knights usually leads to quiet positional play, though there are some sharp variations. The ECO codes for the Four Knights Game are C49 (Symmetrical Variation, 4.Bb5 Bb4), C48 (4.Bb5 without 4…Bb4), C47 (4.d4 and others).

Notable Games include:
Paulsen vs B Raphael ½-½ 1857
Paulsen vs Morphy 0-1 1857
Steinitz vs Zukertort 0-1 1886