Scotch Gambit, London Defense

The London Defense meets the Scotch Gambit with 4...Bb4+, exploiting the fact that the d4-pawn still controls c3. The check forces White to choose between blocking on d2 and pushing c3, and the extra pawn complicates White's usual development. The engine regards the position as balanced and counts the check among Black's best options.

The overwhelmingly common reply is 5. c3, which offers more material. After 5...dxc3 White can continue 6. O-O, and if Black grabs a second pawn with 6...cxb2 7. Bxb2, White is two pawns down but has fast development and very active pieces. Black more often declines that pawn with 6...d6 or 6...Nf6. The other main option after 5...dxc3 is 6. bxc3. The position after 5...dxc3 also arises from the Göring Gambit by 4. c3 dxc3 5. Bc4 Bb4. The modest 5. Bd2 avoids further sacrifices but scores worse for White in online games than 5. c3, after which White's results are good.