Breyer Variation

The Breyer Variation answers 1...c6 with 2. d3, a modest move that supports the e4-pawn instead of building a broad center with 2. d4. If Black plays ...d5 and later captures on e4, White recaptures with the d-pawn and keeps a pawn on e4, avoiding the structural commitments of the main lines. White usually follows with a King's Indian Attack arrangement of knights on d2 and f3, a kingside fianchetto and short castling. The position also arises by transposition from 2. Nf3 d5 3. d3.

Almost every game continues 2...d5. After 3. Nf3 dxe4 4. dxe4 Qxd1+ 5. Kxd1 the queens leave the board at once and White's king forfeits castling; this endgame has drawn more interest in the 21st century and is often reached through the 2. Nf3 move order. In the same line White can instead offer a pawn with 3. Nf3 dxe4 4. Ng5, a sharp try that sets traps. More common is 3. Nd2, which removes the pin on the d-file so that ...dxe4 can be met by dxe4 with queens kept on. The usual answer is 3...e5, leaving the central tension intact and giving Black a pawn pair on d5 and e5 against White's compact e4–d3 setup.

The Stein Attack, 3. Nd2 g6 4. Ngf3 Bg7 5. g3 e5 6. Bg2 Ne7 7. O-O O-O 8. b4, arises when Black also fianchettoes. With the centers locked in mutual tension and both kings castled short, White turns to the queenside, using the b-pawn to gain space and prepare b5 against the c6-pawn that anchors Black's chain.

On move two Black occasionally prefers 2...d6 or 2...e6, while 2...e5 is essentially a move-order choice that lets Black decide later between ...d5, transposing to the main line, and the more restrained ...d6. White generally reaches the King's Indian Attack structure regardless.

The variation is named after Gyula Breyer, who played it against Efim Bogoljubov in 1920 with a different piece deployment: 2...d5 3. Nd2 Nf6 4. Ngf3 Bg4 5. Be2. The fianchetto plan with g3 and Bg2 was introduced by Siegfried Wolf against William Winter in 1930. The line is considered unambitious, yet it is a frequently reached sideline; results in the Lichess database are evenly split and engines rate the position as roughly balanced.