Chess Openings Lab
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Blackmar-Diemer Gambit: Diemer-Rosenberg Attack

The Diemer-Rosenberg Attack is 3.Be3, guarding d4 with the bishop before trying to win back e4. White plans f3 or Nd2 to recover the pawn, while Black uses the time to develop and hold the e4 pawn.

Moves
1.d4 d5 2.e4 dxe4 3.Be3
ECO
D00
Engine
−1.03 · a clear edge for Black (Stockfish 17.1, depth 20)
Played
209 games in our lichess sample
White scores
47.6%

Key ideas for both sides

White

  • Nd2 and later f3 or Qe2 aim at the e4 pawn without opening the f-file too early.
  • Ne2 and g3 with Bg2 build a fianchetto that piles up on e4, as in two engine lines.
  • c4 grabs queenside space if Black spends time holding e4 with ...Bf5.

Black

  • 3...Nf6 is the engine's first choice; it defends e4 and develops before White can play f3.
  • ...Bf5 supports e4, and ...h5 answers h3 so the bishop keeps its diagonal.
  • ...e6 and ...Be7, or ...c6 and ...Bf5, are calm ways to keep the extra pawn.

Plans and pawn structure

Without Nc3, White's pieces do not hit e4 quickly, so Black often keeps the pawn for a while. White builds slowly with Ne2, Nd2 and a kingside fianchetto, hoping to round up e4. Black supports the pawn with ...Bf5 and ...Nbd7, or gives it back at the right moment for development. The bishop on e3 can become a target for ...Ng4 or ...Nd5.

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 −1.03: a clear edge for Black. Its three top choices for Black:

  1. −1.03 3...Nf6 4.Ne2 Bf5 5.h3 h5 6.c4
  2. −0.57 3...e6 4.Nd2 Nf6 5.c3 Be7 6.g3
  3. −0.53 3...c6 4.Ne2 Bf5 5.g3 Nf6 6.Bg2

Pawns, from White's side.

How it scores on lichess

209 rated lichess games reached this position; White scored 47.6%.

under 120033.0%
1200–159960.0%
1600–199941.1%

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

How to play against it

Develop with 3...Nf6 and support e4 with ...Bf5. White has no quick way to win the pawn back, so keep pieces coordinated and avoid trading your light-squared bishop for nothing. White managed only 47.6% overall in this line, so steady development is enough.

Questions

What are the moves of the Blackmar-Diemer Gambit: Diemer-Rosenberg Attack?

The Blackmar-Diemer Gambit: Diemer-Rosenberg Attack starts 1.d4 d5 2.e4 dxe4 3.Be3. Its ECO code is D00.

Is the Blackmar-Diemer Gambit: Diemer-Rosenberg Attack good for White?

Stockfish 17.1 rates the position −1.03 at depth 20, which is a clear edge for Black. In 209 lichess games from our sample, White scored 47.6%. A slow, offbeat try that suits White players who dislike sharp gambits, but it gives Black an easy start.

What is the main idea of the Blackmar-Diemer Gambit: Diemer-Rosenberg Attack?

White protects d4 with Be3 before going after the e4 pawn. The cost is time: Black develops with ...Nf6 and ...Bf5 and often keeps the extra pawn into the middlegame.

What should Black play next?

The engine's first choice is Nf6, with e6 and c6 close behind. 3...Nf6 develops and defends e4 at once, and ...Bf5 next holds the extra pawn.

Updated October 2026. Sources and method.