Staunton Gambit, Nimzowitsch Variation

The Nimzowitsch Variation meets 4. Bg5 with 4...b6 instead of the 4...c6 of the Chigorin Variation. It prepares ...Bb7, which would place the bishop on the long diagonal behind the extra pawn on e4. White most often answers 5. Bxf6, eliminating the knight that guards e4. The main alternative is 5. f3, which strikes at the pawn at once. The line is seldom played, and the engine gives White a slight edge.