Chess Openings Lab
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Caro-Kann Defense: Advance Variation, Bayonet Attack

The Bayonet Attack is 3...Bf5 4.g4, where White chases the f5 bishop with the g-pawn right away. White wants to gain kingside space and trap or misplace the bishop, while Black looks to use the weakened light squares and hit back with ...e6 and ...c5.

Moves
1.e4 c6 2.d4 d5 3.e5 Bf5 4.g4
ECO
B12
Engine
+0.16 · level (Stockfish 17.1, depth 20)
Played
1,295 games in our lichess sample
White scores
54.7%

Key ideas for both sides

White

  • Against 4...Bg6, Ne2 and Nf4 attack the bishop, then h4 threatens h5 to win it.
  • After 4...Be4 5.f3 Bg6, the pawn sacrifice 6.e6 opens the e-file and f7 toward Black's king.
  • Be3 and Nc3 with long castling suit the space White has taken.

Black

  • 4...Be4 is the engine's first choice; it provokes f3 so White's knight loses that square.
  • Meet h4 with ...h5 so the bishop on g6 keeps a retreat.
  • ...e6, ...c5 and ...Ne7 strike at d4 while White's pawns are far up the board.

Plans and pawn structure

White's g4 and e5 pawns give kingside space but leave f4, f5 and h4 loose and the king without a clear home. White wants Ne2, Nf4, h4 and possibly long castling. Black's bishop must survive first, on e4 or g6, then ...e6 and ...c5 hit the center. If Black opens the position before White's pieces are ready, the advanced pawns become targets.

What the engine plays from here

Stockfish 17.1 at depth 20 rates the position +0.16: level. Its three top choices for Black:

  1. +0.16 4...Be4 5.f3 Bg6 6.e6 Qd6 7.exf7+
  2. +0.25 4...Bg6 5.Ne2 e6 6.Nf4 Ne7 7.h4
  3. +0.40 4...Bd7 5.Be3 e6 6.Nc3 c5 7.dxc5

Pawns, from White's side.

How it scores on lichess

1,295 rated lichess games reached this position; White scored 54.7%.

under 120058.6%
1200–159953.0%
1600–199955.3%
2000 and up54.0%

Light: White wins. Grey: draws. Dark: Black wins. About the sample.

How to play against it

Play 4...Be4 and after f3 drop back to g6. Expect the e6 sacrifice and recapture with the bishop on f7, as in the engine line. Do not let the bishop get trapped by h4 and h5; check its escape squares before developing other pieces.

Questions

What are the moves of the Caro-Kann Defense: Advance Variation, Bayonet Attack?

The Caro-Kann Defense: Advance Variation, Bayonet Attack starts 1.e4 c6 2.d4 d5 3.e5 Bf5 4.g4. Its ECO code is B12.

Is the Caro-Kann Defense: Advance Variation, Bayonet Attack good for White?

Stockfish 17.1 rates the position +0.16 at depth 20, which is level. In 1,295 lichess games from our sample, White scored 54.7%. A sharp choice for White players who enjoy aggressive pawn moves; Black needs to know the bishop retreats by heart.

What is the main idea of the Caro-Kann Defense: Advance Variation, Bayonet Attack?

White uses the g-pawn to attack the f5 bishop at once, gaining kingside space and threatening to trap it. Black answers with ...Be4 or ...Bg6 and then strikes the center with ...e6 and ...c5.

What should Black play next?

The engine's first choice is Be4, with Bg6 and Bd7 close behind. 4...Be4 provokes f3, taking the f3 square from White's knight before retreating to g6.

Updated October 2026. Sources and method.