King's Gambit Accepted:Fischer Defense

The defence Bobby Fischer recommended in his 1961 article “A Bust to the King’s Gambit”: Black plays 3...d6 to keep the e5 square from White’s knight.

It is reached after 6 moves: 1. e4 e5 2. f4 exf4 3. Nf3 d6. It is a line of the King's Gambit Accepted.

White is to move and has 29 legal moves. Over the next four moves — two for each side — the game can branch into 854,861 different games. Those games reach 282,374 different positions: most positions can be reached in more than one way, 3 on average.

The Lichess opening list names 5 further lines after this position, such as Greco Gambit (4. Bc4 h6 5. d4 g5 6. h4 Bg7) and Schulder Gambit (4. b4).

The same moves can be played in 9 different legal orders that all reach this position. For example 1. f4 e5 2. e4 exf4 3. Nf3 d6, which starts as the Bird Opening.