Bonet Gambit

The Bonet Gambit arises when White meets the Modern Line, 3. Nf3 Nf6, with 4. Bg5 instead of the usual 4. Nc3 or 4. e3. The bishop pins the f6-knight and develops outside the pawn chain. Nothing protects the c4-pawn, however, so White in effect offers it. 4...dxc4 is one of the engine's preferred replies, and Black can then think about backing the extra pawn with ...b5, as in other Slav lines. Engines also suggest 4...Ne4, which attacks the bishop at once, and 4...Bf5, which develops the queen's bishop while c8 can still be left freely.

In practice Black most often declines the pawn with 4...e6. This shores up d5 and gives the game a Semi-Slav character. 4...Bg4 and 4...Bf5 come next in popularity, and both get the bishop out before ...e6. The engine assessment is close to balanced, tilted very slightly toward Black. The line is a fairly uncommon sideline among named openings. In online games draws are rare and White scores marginally better.