Blackmar-Diemer Gambit
Initial Moves: 1.d4 d5 2.e4
Strategic Summary & Main Idea
The Blackmar-Diemer Gambit gives up the e4 pawn on move two and, with f3, offers the f-pawn as well, in return for the open f-file and a quick attack on Black's castled king. The measurement is harsh on the gambit: the position after 2.e4 is −0.65, and after 4.f3, −0.74. Of the four measured defences that accept the second pawn, only one leaves White better, the Teichmann (+0.11), precisely the one that gives up the bishop pair. The Ziegler, with ...c6 and ...Bf5, measures −0.83, and the queen recapture, the Ryder Variation, −1.66.
The pawn structure this opening produces
The Blackmar-Diemer produces a structure in which White has neither an e-pawn nor an f-pawn, and that defines both sides' plans. After 4.f3 exf3 5.Nxf3, White has a lone d4 pawn in the centre, a half-open f-file for the rook and an open e-file for the other rook or the queen. Black has an extra pawn and an intact kingside structure, and the plan is simple: finish development, castle and trade pieces. White's attack follows a known script — Bd3 or Bc4, short castling, Qe1 and Qh4, and rooks on f1 and e1 against f7 and f6. When it does not arrive, what remains is the d4 pawn with no e-pawn beside it, which Black blockades on d5 and attacks with ...c5 and ...Nc6. In the defences that decline the second pawn, such as the O'Kelly with ...c6 or the Langeheinecke with ...e3, the structure is less open and the gambit loses its only argument: the f-file does not open and the pawn given buys nothing.
Typical Plans for White
- Develop with Nxf3, Bd3 or Bc4 and castle before any attack
- Bring the queen to h4 via e1 and the rooks to the e- and f-files against f7
- Recapture on f3 with the knight, never with the queen: the Ryder Variation measures −1.66
- Against the Teichmann, play h3 and force the exchange on f3: it is the only measured acceptance with a White edge
- Against the Lemberger, take on e5 and trade queens; 4.Qh5 measures −1.02
Typical Plans for Black
- Accept both pawns and develop with ...e6 and ...Be7 or with ...c6 and ...Bf5
- Castle early and trade pieces: every exchange reduces the attack that justifies the pawn
- Blockade the d4 pawn on d5 and attack it with ...c5 once White's attack has passed
- Do not decline with ...c6 or ...e3: both declines measure worse for Black than the Euwe, the Bogoljubov and the Ziegler
- Avoid ...e5 after 4.f3: the break opens the centre with Black's king still at home
Main Variations of the Blackmar-Diemer Gambit
| Variation | Move Sequence | Evaluation | Style / Characteristic |
|---|---|---|---|
| Euwe Defence (5...e6) | 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 e6 6.Bg5 Be7 7.Bd3 |
−0.39 | The most solid reply; the c8 bishop stays behind e6 |
| Teichmann Defence (5...Bg4) | 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 Bg4 6.h3 Bxf3 7.Qxf3 c6 |
+0.11 | Black gives up the bishop pair; the only acceptance in which White measures better |
| Bogoljubov Defence (5...g6) | 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 g6 6.Bc4 Bg7 7.O-O O-O |
−0.69 | Fianchetto against the f-file; the g7 bishop closes the attacking diagonal |
| Ziegler Defence (5...c6) | 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 c6 6.Bc4 Bf5 |
−0.83 | The bishop comes out before ...e6; the lowest evaluation among the normal lines |
| Vienna Defence (4...Bf5) | 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 Bf5 |
−0.59 | The bishop defends e4 instead of accepting the second pawn |
| Lemberger Countergambit (3...e5) | 1.d4 d5 2.e4 dxe4 3.Nc3 e5 4.dxe5 Qxd1+ 5.Kxd1 |
−0.34 | The countergambit that trades queens and leaves White's king in the centre |
| O'Kelly Defence (4...c6) | 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 c6 |
−0.19 | The decline that prepares ...Qb6; it costs two to six tenths against the acceptances with ...e6, ...g6 and ...c6 |
| Langeheinecke (4...e3) | 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 e3 |
+0.39 | The pawn returned to close the c1 diagonal; Black's most expensive decline |
Evaluations measured by us with Stockfish 19, depth 22, on 15/09/2026.
Frequently asked questions
Is the Blackmar-Diemer Gambit sound?
Not by the measurement. The position after 2.e4 is −0.65, and after 4.f3, −0.74. Of the four acceptances measured in this entry, three leave Black better, between −0.39 and −0.83. The gambit pays in fast games against players who do not know the defence, not against correct development.
What is the best defence to the Blackmar-Diemer?
The Ziegler, with 5...c6 and ...Bf5, which measures −0.83, and the Bogoljubov, with 5...g6, which measures −0.69. Both accept the two pawns and complete development before White's attack arrives. The Euwe, with ...e6, is more passive and measures −0.39.
Is it worth declining the gambit?
No. The O'Kelly, with 4...c6, measures −0.19, and the Langeheinecke, with 4...e3, +0.39 — both worse for Black than accepting. The pawn given is the reason Black is better; returning it without need is the only way to give the gambit what it cannot earn alone.
Common Mistakes & Where Most Amateurs Go Wrong
- 01 Recapturing on f3 with the queen, the Ryder Variation. With 5.Qxf3 the d4 pawn is undefended: 5...Qxd4 6.Be3 gives White development, but now it is two pawns down, and the position goes from −0.74 to −1.66. The line:
1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Qxf3 Qxd4 6.Be3−1.66 - 02 Meeting the Lemberger with 4.Qh5?, attacking e5. The queen comes out early with no real target, and 4...exd4 hits the c3 knight: −1.02, against −0.34 for the 4.dxe5 exchange. The line:
1.d4 d5 2.e4 dxe4 3.Nc3 e5 4.Qh5−1.02 - 03 Breaking with 4...e5? instead of accepting the second pawn, the Gunderam Variation. The centre opens with Black's king still on e8, and 5.dxe5 hands White back the pawn and the initiative: +1.13. The line:
1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 e5+1.13
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