Four Knights Variation

Reached through the Taimanov move order, 5...Nf6 attacks e4 and prepares ...Bb4, pinning the c3-knight and threatening the pawn it defends. Its best-known use is as a transfer into the Sveshnikov: 6. Ndb5 d6 7. Bf4 e5 8. Bg5 a6 9. Na3 b5 reaches the main line while sidestepping the Rossolimo and the 7. Nd5 lines available in the usual Sveshnikov order. The cost is that White gains 6. Nxc6 bxc6 7. e5 Nd5 8. Ne4, the Exchange Variation, which is the most common reply in the database; 6. Be3 is also frequent, and Black scores well against it.

After 6. Ndb5, Black can avoid the Sveshnikov with 6...Bb4, when 7. a3 Bxc3+ 8. Nxc3 d5 9. exd5 exd5 concedes the bishop pair for active pieces and the ...d4 advance, while 7. Nd6+ is the American Attack. The Cobra Variation, 6...Bc5 7. Bf4 O-O 8. Bc7 Qe7 9. Bd6 Bxd6 10. Qxd6, can lead to a drawish ending after 10...Ne8 11. Qxd7 Nxd7. The engine gives White a slight edge, though Black scores marginally better in practice.