Steinitz Defense, Nimzowitsch Attack

The Nimzowitsch Attack is the branch of the Steinitz Defense in which White, after 4. d4 Bd7 5. Nc3 Nf6, gives up the bishop pair with 6. Bxc6 instead of castling. The exchange removes the c6 knight, one of the defenders of e5, and keeps the central tension high. Black usually recaptures 6...Bxc6, keeping the pawn structure intact. The rarer 6...bxc6 scores worse for Black in practice. Engines rate White's position as clearly better.