Chess Openings Lab
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Blackmar-Diemer Gambit Accepted: Teichmann Defense

The Teichmann Defense arises after 5.Nxf3 Bg4, when Black pins the f3 knight that guards d4. White wants open lines and a kingside attack for the pawn, while Black plans ...e6, ...c6 and possibly ...Bxf3 to win the d4 pawn too.

Moves
1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 Bg4
ECO
D00
Engine
−0.16 · level (Stockfish 17.1, depth 20)
Played
1,413 games in our lichess sample
White scores
56.8%

Key ideas for both sides

White

  • Ask the bishop at once with 6.h3. After 6...Be6 the engine line continues 7.Bg5, 8.Qd2 and Bd3.
  • If Black takes on f3, recapture with the queen. Qxf3 eyes b7 and the f-file, and Be3 then covers d4.
  • Castle on either side, then put a rook on the half-open f-file and aim the c1 bishop at g5 against the f6 knight.
  • Bc4 targets e6 and f7, the natural square once Black plays ...e6 to block the bishop's diagonal.

Black

  • Keep the pin and add pressure on d4 with ...e6, ...c6 and ...Nbd7. White has no e-pawn left to support it.
  • Trading with ...Bxf3 removes the key d4 defender, and ...Qxd4 can follow if White recaptures carelessly.
  • Against 6.h3, retreat to e6 and fianchetto with ...g6 and ...Bg7, as the top engine line shows.
  • Do not castle short into the open f-file too soon; ...c6 and ...Qd7 keep long castling as an option.

Plans and pawn structure

The structure is lopsided: White has d4 and an open f-file, Black has an extra pawn and no d-pawn. White develops with Bd3 or Bc4, castles, and doubles rooks on the central and f-files, hoping for Ne5 or a strike on f7. Black clears the queen's path with ...e6 and ...c6, then decides between ...Bxf3 to win d4 and keeping the bishop as a defender. If Black keeps the extra pawn and trades pieces, the endgame favors Black.

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 −0.16: level. Its three top choices for White:

  1. −0.16 6.h3 Be6 7.Bg5 g6 8.Qd2 c6
  2. −0.44 6.Bc4 e6 7.h3 Bxf3 8.Qxf3 c6
  3. −0.63 6.Be3 e6 7.h3 Bf5 8.Bd3 Bb4

Pawns, from White's side.

How it scores on lichess

1,413 rated lichess games reached this position; White scored 56.8%.

under 120057.8%
1200–159956.3%
1600–199959.0%
2000 and up48.4%

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

Where it goes next

  • Teichmann Defense, Seidel-Hall Attack6.h3 · rare

How to play against it

Play 6.h3 first and settle the bishop's future before committing other pieces. If it takes on f3, recapture with the queen and keep d4 covered with Be3 rather than allowing ...Qxd4 with gain of time. Avoid slow pawn moves on the queenside; your compensation is development and the f-file, and it fades quickly.

Questions

What are the moves of the Blackmar-Diemer Gambit Accepted: Teichmann Defense?

The Blackmar-Diemer Gambit Accepted: Teichmann Defense starts 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 Bg4. Its ECO code is D00.

Is the Blackmar-Diemer Gambit Accepted: Teichmann Defense good for Black?

Stockfish 17.1 rates the position −0.16 at depth 20, which is level. In 1,413 lichess games from our sample, White scored 56.8%. Good for a solid Black player who wants to keep the pawn without heavy theory; White needs patience after h3.

What is the main idea of the Blackmar-Diemer Gambit Accepted: Teichmann Defense?

Black develops the light-squared bishop to g4 before ...e6 can lock it in, pinning the f3 knight that guards d4. White answers with h3, and the fight is about whether Black can win d4 or White can make use of the f-file.

What should White play next?

The engine's first choice is h3, with Bc4 and Be3 close behind. 6.h3 asks the bishop to decide at once, and after ...Be6 White continues with Bg5 and Qd2.

Updated October 2026. Sources and method.