The idea in one sentence
Black lets White build a big pawn centre on purpose, then attacks it with the bishop on g7 and ...c5: the centre is a target, not a strength.
♔ White's plans
- Build the big centre with e4 and c3
- Defend d4 with Be3 and Rc1
- Push d5 or attack on the kingside when the centre holds
♚ Black's plans
- Trade on c3 to bring a pawn to c3 that can be attacked
- Hit d4 with ...Bg7, ...c5 and ...Nc6
- Use the queenside majority later
Pawn structure. White's broad centre c3-d4-e4 against Black's pressure on d4.
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...d5 strikes the centre at once.
- 4...Nxd5 recaptures.
- 5.e4 kicks the knight and builds the centre.
- 5...Nxc3 trades so that White's centre can be attacked.
- 6...Bg7 aims at d4.
- 7...c5 adds a second attacker on d4.
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.