The idea in one sentence
Black lets White build a big centre, then attacks it with pieces and the fianchettoed bishop, waiting for ...c5 or ...e5.
♔ White's plans
- Build the centre with e4 and d4
- Develop and castle, keeping the centre firm
- Gain space with e5 or attack with f4
♚ Black's plans
- Fianchetto the bishop on g7 to hit d4
- Castle quickly
- Strike the centre with ...e5 or ...c5
Pawn structure. Black's flexible d6-g6 against White's broad centre.
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
- 1...d6 prepares ...Nf6 without allowing e5 to kick the knight.
- 2...Nf6 attacks e4.
- 3...g6 prepares the fianchetto.
- 4...Bg7 aims the bishop at the long diagonal and 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.