Gunsberg Defense

The Gunsberg Defense, also called the Gunsberg Variation, is Black's direct approach after 1. d4 d5 2. c4 dxc4 3. Nf3. Instead of preparing the thrust against the center with ...Nf6 and ...e6, Black plays 3...c5 at once. For the moment Black's c-pawns stand doubled on c4 and c5, and Black is a pawn up. White has to decide whether to recover c4 quietly or to use the d4-pawn to gain space. The engine gives White a slight edge, and White has scored well in online games.

The most common reply is 4. e3. It prepares Bxc4 and tends toward the open, isolated-pawn type of positions familiar from the classical lines. 4. d5 is the most ambitious answer and White's best-scoring choice. The advanced pawn cramps Black and takes away c6 from the queen's knight, while Black relies on the extra c4-pawn and queenside counterplay. 4. Nc3 and 4. e4 are also played. The related Prianishenmo Gambit comes from a different order, 3...Nf6 4. Nc3 c5 5. d5 e6 6. e4 exd5 7. e5, where White gives up material to drive the knight away from f6.