Bishop's Gambit, Cozio Defense

The Cozio Defense answers the Bishop's Gambit with 3...Nf6. Black does not check on h4 and does not return the pawn at once. The knight develops with gain of time against e4 and supports a later ...d5. White's king keeps its castling rights, so the game turns on a race between White's development and Black's central counterplay rather than on the king hunts that follow 3...Qh4+. Engines rate the position as roughly balanced with a marginal lean toward Black, while White scores slightly better in online games.

The most common reply is 4. Nc3, which defends e4 and leads to the Bogoljubow Variation. There Korchnoi and Zak recommend 4...c6, which can also arise from 3...c6 4. Nc3 Nf6. Its main line runs 5. Bb3 d5 6. exd5 cxd5 7. d4 Bd6 8. Nge2. Black gets an open center and active pieces in return for the extra f4-pawn. The next most popular replies, 4. Nf3 and 4. e5, are played about equally often. The advance 4. e5 drives the knight away at once, and in that line results are close to even.