The idea in one sentence
White gains space with e5; Black develops the bishop outside the chain first, then attacks d4 with ...c5.
♔ White's plans
- Gain space with e5
- Develop quietly: Nf3, Be2, castle
- Gain more space with c3 or c4, or attack the bishop with g4 and Nh4
♚ Black's plans
- Put the bishop on f5 before ...e6
- Hit d4 with ...c5
- Develop the queen's knight to c6 or d7
Pawn structure. Like the French Advance, but Black's light-squared bishop is outside the pawn chain.
How to learn it
- Read the idea and the plans: every move below serves one of them.
- In the story, ask of each move: what does it do, what does it stop, what does it prepare, why not the other one?
- Drill your side. At the key moves you name the idea first, then play the move.
- Missed moves come back first next time, and in your journal.
The defining moves
- 3.e5 gains space.
- 3...Bf5 develops the bishop before ...e6 locks it in.
- 4...e6 builds the chain.
- 5...c5 hits d4. The c-pawn took two moves to get there, but White's quiet setup cannot punish the lost time.
The line follows the moves masters play most (Lichess masters database), each checked by Stockfish 19 at depth 22; where the book move is not Stockfish's first choice, the story says so. Scores are in pawns from White's side: +0.30 is good for White, −0.30 for Black.