Classical Defense

The Classical Defense meets the Double Danish with 5...Nf6. It develops a piece and immediately hits the e4-pawn, which neither White's c4-bishop nor the b2-bishop protects. White is two pawns down and must deal with this threat before continuing the attack. The usual answer is 6. e5, chosen in well over half of games. It counterattacks the knight instead of defending the pawn and is generally rated White's best try. Protecting e4 with 6. Nc3, or with 6. Nd2 to keep the long diagonal open, is less common, and the central break ...d5 undermines the pawn anyway.

The calm 6. Nf3 allows Black to reply with natural development such as kingside castling. 6. Qb3 eyes f7, but 6...d5 is a strong answer, since 7. e5 dxc4 8. exf6 leaves the queen badly placed. Exchanging with 6. Bxf6 is poor: it gives up the bishop pair, and the queen on f6 attacks a1 and f2. Engines slightly favor Black after 5...Nf6, yet in online play White wins considerably more often than Black.