Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Nc3/3...Nf6/4. d4/4...exd4/5. Nxd4

Scotch variation accepted C47 Four knights game → Scotch variation → Accepted 5. Nxd4 White recovers the pawn. It is inaccurate for Black to initiate the trade of knights. 5...Nxd4?! 6. Qxd4 and White stands better: their queen is activated and Black cannot gain tempo on it. On the other hand, White is very happy to trade the knights on c6 with tempo on Black's queen, and does so in several lines. 5...Bb4 is the main line, pinning White's knight and so removing the defender of the e4-pawn. Were White to defend e4 with 6. Bd3?, they obstruct the queen's vision of d4 and their knight falls. Therefore, White trades knights first, 6. Nxc6 bxc6 (Black avoids the queen trade after 6...dxc6) 7. Bd3, and after 7...d5 8. exd5 cxd5 Black undoubles their pawns. Note that 6. Bd2? to interrupt the pin neither saves the pawn (6...Bxc3?! 7. Bxc3 Nxe4) nor the knight (6...Nxd4!). A less common sideline is to develop the bishop to 5...Bc5 instead, where there are a number of reasonable moves, top of which being 6. Be3 or 6. Nxc6. 5...Nxe4, the Schmid defence, is an alternative. This is a temporary knight sacrifice: after 6. Nxe4, Black pins the knight with 6...Qe7, and White cannot play 7. Qe2? without dropping the other knight. The line continues 7. f3 d5 8. Bb5 Bd7 9. Bxc6 bxc6 10. O-O dxe4 11. Re1 O-O-O 12. Rxe4 where material is equal and the board is open and unbalanced. Theory table References See also