Lamb Defense

The Lamb Defense is one of the less common ways of declining the Blackmar-Diemer Gambit. Instead of capturing on f3, Black develops with 4...Nc6. The knight attacks d4 at once and leaves the extra pawn on e4, so White must decide whether to win the pawn back immediately or gain space. The drawback is that the knight on c6 offers White a target for a gain of tempo with the d-pawn. Engines rate the position as roughly level and prefer 5. d5, 5. Bb5 or 5. Be3.

In practice 5. fxe4, which simply recovers the pawn, is the most popular reply, but Black scores well after it. The thrust 5. d5 gives White the best results. Black usually answers it with 5...Ne5, because 5...Nb4 is considered playable but weaker. After 5...Ne5, 6. Qd4 lets Black set a tactical trap with 6...exf3, so 6. fxe4 e6 7. Nf3 is regarded as the sounder course. The pin with 5. Bb5 is the quieter alternative, and 5. Be3 protects d4 while White keeps developing.