Two Knights Defense - Sidelines (4.O-O)
White castles early with 4.O-O, skipping c3, so grab the e4 pawn with ...Nxe4. After 5.Re1 d5 6.Bb5 Bc5, meet 7.d4 with ...exd4, and if 8.Nxd4 castle with O-O. Watch for 5.Re1, a common mistake you punish. You land up a pawn with a strong attack, sometimes even winning material outright.
Let's learn the 4.O-O Lines! White castles kingside, then pins our knight with 6.Bb5. We counter with ...Bc5, threatening a fork and ending up a pawn with a strong attack. Let's begin with 1.e4.
Learn this chapter freeMain line
Scroll the moves: the board follows.
Key lines
The free lines of this chapter, each one trainable move by move.
- Main Line
… 6. Bb5 Bc5 7. d4 exd4 8. Nxd4 O-O
- 5. d4
… 4... Nxe4 5. d4 d5 6. Bb3 exd4 7. Nxd4 Bc5 8. Nxc6 bxc6 9. Nd2 Bf5
- 5. d4
… 4... Nxe4 5. d4 d5 6. Bb5 exd4 7. Nxd4 Bd7 8. Bxc6 bxc6 9. Re1 Bd6
- 5. d4
… 4... Nxe4 5. d4 d5 6. Bb5 exd4 7. Nxd4 Bd7 8. Re1 Bd6 9. f3 Nxd4 10. Bxd7+ Kxd7 11. fxe4 Qh4 12. e5 Bc5
- Trap: 5.Re1, you win the queen
… 5... d5 6. Bb3 Bc5 7. d4 Nxd4 8. Nxd4 Bxd4 9. Re2 Bg4 10. c3 Bxf2+ 11. Rxf2 Bxd1 12. Bxd1 Nxf2 13. Be2 O-O
- 6. Bb3
… 5... d5 6. Bb3 Bc5 7. d4 Nxd4 8. Nxd4 Bxd4 9. Be3 Bxb2 10. Bxd5 Nf6
Other chapters
Modern Bishop's Opening (4.d3)
White enters the Italian with Bc4 and settles for the quiet 4.d3. Meet it with ...Be7, castle, and after 6.c3 d5 7.exd5 Nxd5, giving your bishop on e7 more room. Aim for an active, comfortable setup where your pieces develop freely and your d5 knight eyes the center.
41 linesPolerio Defense (5...Na5)
White checks with 6.Bb5+, so block with ...c6 and recapture ...bxc6, then meet 8.Bd3 with ...Nd5 and ...Nf4 to grab the bishop. Castle, let White take on e5, and push ...c5, even though it lands isolated. Watch for the 8.Ba4 trap where ...Qd4 nets you a piece. You reach the bishop pair against White's isolated and doubled d-pawns.
22 linesItalian Variation (4.Nc3 Nxe4)
After 4.Nc3, take the pawn with Nxe4 and meet Nxe4 with d5, hitting bishop and knight at once. Follow up Qxd5, Qd6, Bg4 pinning the knight, and Bh5 to keep it pinned. Castle queenside, then push f5 and f4 with the bishop pair.
9 linesOpen Variation (4.d4)
White opens the center with 4.d4, steering you into the Scotch Gambit. Meet it with 4...exd4, 5...d5, 6...Ne4 and 7...Bc5, then castle with 8...O-O and defend your knight with 12...Qe7. You land in a position with an isolated c7 pawn against White's queenside majority.
13 lines
Learn Sidelines (4.O-O) on the board
The trainer plays the opponent's moves and waits for yours, line by line. Free to start.
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