French Defense:Alekhine-Chatard Attack

Named after Alexander Alekhine and Eugène Chatard. White offers a pawn with 6. h4 to speed up a kingside attack.

It is reached after 11 moves: 1. e4 e6 2. d4 d5 3. Nc3 Nf6 4. Bg5 Be7 5. e5 Nfd7 6. h4. It is a line of the French Defense.

Black is to move and has 29 legal moves. Over the next four moves — two for each side — the game can branch into 1,550,215 different games. Those games reach 499,447 different positions: most positions can be reached in more than one way, 3.1 on average.

The Lichess opening list names 5 further lines after this position, such as Breyer Variation (6... c5) and Maróczy Variation (6... a6).

The same moves can be played in 3,600 different legal orders that all reach this position. For example 1. e4 e6 2. Nc3 d5 3. d4 Nf6 4. Bg5 Be7 5. e5 Nfd7 6. h4, which starts as the French Defense: Queen's Knight.