Chess Openings Lab
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Caro-Kann Defense: Rasa-Studier Gambit

The Rasa-Studier Gambit is 3.Nc3 dxe4 4.f3, a Blackmar-Diemer style pawn offer against the Caro-Kann. White gives the e-pawn for an open f-file and fast development, while Black can take on f3 and keep a sound extra pawn.

Moves
1.e4 c6 2.d4 d5 3.Nc3 dxe4 4.f3
ECO
B15
Engine
−0.71 · a slight edge for Black (Stockfish 17.1, depth 20)
Played
658 games in our lichess sample
White scores
57.0%

Key ideas for both sides

White

  • After ...exf3, recapture Nxf3 and aim Bd3, O-O and Qe1 or Qd3 at the kingside along the open f-file.
  • Play h3 to stop ...Bg4, as in the first engine line, so the f3 knight stays strong.
  • If Black declines with ...Nf6, take back on e4 with the knight and play for normal development.

Black

  • Take with 4...exf3, the engine's top choice, and develop with ...Nf6 and ...Bf5.
  • Trade White's attacking bishop with ...Bf5 and ...Bxd3 when it lands on d3.
  • The ...e5 counter-strike leads to an early queen trade, a safe way to kill White's attack.
  • Castle short quickly and keep the f-file covered with pieces, not pawn moves.

Plans and pawn structure

If Black accepts, White has the f-file and a lead in development but is a pawn down with a loose center on d4. White plays Nxf3, Bd3, O-O and Qe1-h4 or a knight to e5, trying for a direct attack. Black's plan is calm: ...Nf6, ...Bf5 to trade the d3 bishop, ...e6, ...Be7 and short castling, then ...Nbd7 and pressure on d4. Once Black is castled, the extra pawn should tell.

Where the engine's main line heads: White pawn d4, no e-pawns for White, no d-pawn for Black. White has a pawn on d4 and no e-pawn; Black has no d-pawn. White has more central space; Black's pieces are free and the d4 pawn is a target.

What the engine plays from here

Stockfish 17.1 at depth 20 rates the position −0.71: a slight edge for Black. Its three top choices for Black:

  1. −0.71 4...exf3 5.Nxf3 Nf6 6.h3 Bf5 7.Bd3
  2. −0.32 4...Nf6 5.Nxe4 Nbd7 6.Nxf6+ Nxf6 7.c3
  3. −0.09 4...e5 5.dxe5 Qxd1+ 6.Nxd1 Nd7 7.Bf4

Pawns, from White's side.

How it scores on lichess

658 rated lichess games reached this position; White scored 57.0%.

1200–159956.1%
1600–199959.3%
2000 and up51.6%

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

How to play against it

As Black, take on f3 and develop. The engine line shows ...Bf5 and ...Bxd3 trading off White's best attacker. Do not play ...g6 or other kingside pawn moves that weaken f6 and h6. As White, this gambit is objectively dubious, so you need to play fast and direct to make it work.

Questions

What are the moves of the Caro-Kann Defense: Rasa-Studier Gambit?

The Caro-Kann Defense: Rasa-Studier Gambit starts 1.e4 c6 2.d4 d5 3.Nc3 dxe4 4.f3. Its ECO code is B15.

Is the Caro-Kann Defense: Rasa-Studier Gambit good for White?

Stockfish 17.1 rates the position −0.71 at depth 20, which is a slight edge for Black. In 658 lichess games from our sample, White scored 57.0%. A dubious gambit that scores reasonably in practice, but Black is better with simple development; it suits attacking players willing to take risks.

What is the main idea of the Caro-Kann Defense: Rasa-Studier Gambit?

White offers the f-pawn to get an open f-file and quick attacking development. Black should accept with ...exf3, trade White's bishop with ...Bf5 and keep the extra pawn.

What should Black play next?

The engine's first choice is exf3, with Nf6 and e5 close behind. 4...exf3 accepts the pawn, and after Nxf3 Black develops ...Nf6 and ...Bf5 to trade White's best attacker.

Updated October 2026. Sources and method.