Blackmar–Diemer Gambit Accepted (D00)

ECO D00 · Vol.16 · Ch.2 · 1. d4 d5 2. e4 dxe4 3. Nc3 Nf6 4. f3 exf3

EPD: rnbqkb1r/ppp1pppp/5n2/8/3P4/2N2p2/PPP3PP/R1BQKBNR w KQkq - · Eval +0.10

Forged by Armand Blackmar and refined into an attacking crusade by Emil Josef Diemer, the Blackmar–Diemer Gambit Accepted (D00: 1. d4 d5 2. e4 dxe4 3. Nc3 Nf6 4. f3 exf3) trades a clear pawn for a half-open f-file and effortless development of every White piece. Once 5. Nxf3 lands on the board, White builds a fierce kingside battery while Black must defend precisely to convert the extra pawn.

Recapture 5. Nxf3 to open the f-file cleanly—your real compensation isn't a cheap one-move trap, it's castling fast so Rf1, Bc4, and Qe1–h4 flood the kingside!

Historical Origins & Pawn-Structure DNA

Octávio Trompowsky (1930s Brazil), Julian Hodgson & Diemer's Gambit Lab · Doubled f6-Pawns Asymmetry & Open Central Gambit Files · Octávio Trompowsky, Julian Hodgson, Emil Josef Diemer, Richard Rapport

Pioneered by Brazilian champion Octávio Trompowsky at the 1939 Buenos Aires Olympiad and turned into a feared grandmaster weapon by British GM Julian Hodgson in the 1990s, 2. Bg5 remains a premier anti-theory disruptor.

In the Trompowsky, White stands ready to capture Bxf6 and inflict inflexible doubled f-pawns unless Black reacts energetically with 2...Ne4, 2...d5, or 2...c5; in Queen's Pawn gambits, rapid castling and open e/f-files override material counting.

White's Strategic Blueprint

Recapture 5. Nxf3 (or ultra-sharp 5. Qxf3 Ryder Gambit hitting d4/b7 sacrifices), develop Bc4 and Bg5/Bf4, and castle short to activate Rf1 immediately.
Execute the classic Diemer queen lift Qe1–h4!, teaming up with Bh6, Ng5, and Rxf6 sacrifice motifs against Black's castled king.
Keep d4 protected with Bd3 or Be3 when Black plays ...Bg4 (Teichmann) or ...g6 (Bogoljubow) so Black never wins a second pawn with tempo.

Black's Counterplay & Breaks

Bring the c8-bishop outside the pawn chain FIRST via 5. Nxf3 Bg4 (Teichmann) or 5...Bf5 (Gunderam) before playing ...e6.
Or adopt Bogoljubow's fortress (5. Nxf3 g6 6. Bc4 Bg7 7. O-O O-O), blunting White's bishops on the dark squares while nursing the extra pawn.
Prepare a timely ...c5 or ...Nc6 + ...Bg4 strike against White's d4-anchor to trade queens or minor pieces and extinguish the attack.

Common Club Traps & Mistakes

Locking in c8 passively with 5. Nxf3 e6?! without active counterplay lets White roll Bg5, Bd3, O-O, and Qe1–h4 into a crushing kingside siege.
As White, going all-in with 5. Qxf3?! Qxd4 6. Be3 Qb4 7. O-O-O (Halosar Trap) is thrilling in blitz, but accurate 6...Qg4! forces a queen trade and leaves White two pawns down.

Canonical ECO Sub-Variations

D00 Blackmar-Diemer Gambit Accepted: 1. d4 d5 2. e4 dxe4 3. Nc3 Nf6 4. f3 exf3 (rnbqkb1r/ppp1pppp/5n2/8/3P4/2N2p2/PPP3PP/R1BQKBNR w KQkq -)
D00 Blackmar-Diemer Gambit Accepted: Bogoljubow Defense: 1. d4 d5 2. e4 dxe4 3. Nc3 Nf6 4. f3 exf3 5. Nxf3 g6 (rnbqkb1r/ppp1pp1p/5np1/8/3P4/2N2N2/PPP3PP/R1BQKB1R w KQkq -)
D00 Blackmar-Diemer Gambit Accepted: Teichmann Defense: 1. d4 d5 2. e4 dxe4 3. Nc3 Nf6 4. f3 exf3 5. Nxf3 Bg4 (rn1qkb1r/ppp1pppp/5n2/8/3P2b1/2N2N2/PPP3PP/R1BQKB1R w KQkq -)
D00 Blackmar-Diemer Gambit Accepted: Euwe Defense: 1. d4 d5 2. e4 dxe4 3. Nc3 Nf6 4. f3 exf3 5. Nxf3 e6 (rnbqkb1r/ppp2ppp/4pn2/8/3P4/2N2N2/PPP3PP/R1BQKB1R w KQkq -)
D00 Blackmar-Diemer Gambit Accepted: Gunderam Defense: 1. d4 d5 2. e4 dxe4 3. Nc3 Nf6 4. f3 exf3 5. Nxf3 Bf5 (rn1qkb1r/ppp1pppp/5n2/5b2/3P4/2N2N2/PPP3PP/R1BQKB1R w KQkq -)
D00 Blackmar-Diemer Gambit Accepted: Teichmann Defense, Classical Variation: 1. d4 d5 2. e4 dxe4 3. Nc3 Nf6 4. f3 exf3 5. Nxf3 Bg4 6. h3 Bxf3 7. Qxf3 c6 8. Be3 (rn1qkb1r/pp2pppp/2p2n2/8/3P4/2N1BQ1P/PPP3P1/R3KB1R b KQkq -)

FAQ

Why does White insert 3. Nc3 Nf6 before playing 4. f3 instead of 1. d4 d5 2. e4 dxe4 3. f3?

Playing 3. f3?! immediately allows 3...e5! (or 3...exf3 4. Nxf3 Bg4 with an easy game), whereas 3. Nc3 forces Black to commit 3...Nf6 first or allow Nxe4.

What is the famous Halosar Trap in the Ryder Gambit (5. Qxf3)?

After 5. Qxf3 Qxd4 6. Be3 Qb4?! 7. O-O-O Bg4??, White uncorks 8. Nb5! threatening Nxc7#—if 8...Bxf3??, 9. Nxc7# is checkmate! (Black avoids it with 6...Qg4!.)

Which defense gives Black the cleanest refutation at tournament time controls?

5. Nxf3 Bg4 (Teichmann Defense) followed by ...e6, ...c6, and ...Nbd7 neutralizes White's key f3-knight and solidifies d5/b7 without loosening kingside pawns.

Grandmasters Who Weaponized This Technique

José Raúl Capablanca (CUB · 8 yrs Unbeaten) — 3rd World Champion · The Human Chess Machine (8 Years Unbeaten)
Viswanathan Anand (IND · 2817 FIDE) — 15th World Champion · The Lightning Kid from Madras
Alexander Alekhine (FRA · 17 yrs Champ) — 4th World Champion · Grand Architect of Deep Combinations

A45 · Trompowsky Attack: 2...Ne4 3. Bh4 Line (A45) · D00 · Blackmar–Diemer Declined & Vienna Defense (D00) · A40 · Englund Gambit: Refuting the 3...Qe7 Trap (A40) · Tarrasch Rule & Active Rook Coordination