King's Gambit Accepted: King's Knight's Gambit (C34)

ECO C34 · Vol.05 · Ch.1 · 1. e4 e5 2. f4 exf4 3. Nf3

EPD: rnbqkbnr/pppp1ppp/8/8/4Pp2/5N2/PPPP2PP/RNBQKB1R b KQkq - · Eval +0.10

Immortalized by Boris Spassky (who defeated Bobby Fischer and David Bronstein with it) and kept razor-sharp by Vassily Ivanchuk, the King's Knight's Gambit (C34: 1. e4 e5 2. f4 exf4 3. Nf3) is the classical mainline of the King's Gambit Accepted. By deflecting Black's e5-pawn on move two and guarding h4 with 3. Nf3, White prepares an unopposed d2–d4 central occupation alongside rapid kingside castling to turn the f1-rook into a battering ram against f4 and f7.

Otto loves how 3. Nf3 slams the door on ...Qh4+ first—build your d4 center calmly before hunting the f4-pawn down the half-open f-file!

Historical Origins & Pawn-Structure DNA

19th-Century Romantic Era & Viennese Coffeehouse Masters (Hamppe, Anderssen) · Open f-File Kingside Storm & Delayed f4 Spearhead · Adolf Anderssen, Paul Morphy, Boris Spassky, Hikaru Nakamura

Immortalized in Anderssen's 1851 'Immortal Game' and championed well into the modern era by World Champion Boris Spassky, the King's Gambit and Carl Hamppe's Vienna Game laid the tactical foundations of sacrifice, tempo, and open-file domination.

By challenging e5 from the flank with f4, White trades temporary king exposure along the a7–g1 diagonal for an open f-file rook lift after O-O and an imposing e4–d4 central pawn duo—while Black's sharpest antidote is a timely ...d5 counter-thrust.

White's Strategic Blueprint

Seize full central control with d2–d4 and Nc3, then target the overextended f4-pawn using Bxf4 after castling short.
Meet Black's ambitious 3...g5 grip with 4. h4! g4 5. Ne5 (Kieseritzky Gambit, C39) to shatter the g5–f4 pawn chain and leap onto f7 or g4.
Against Fischer's solid 3...d6 or Becker's 3...h6, deploy Bc4 and d4 smoothly, piling pressure along the half-open f-file with O-O and Qe1–h4.

Black's Counterplay & Breaks

Strike back in the center with the Modern Abbazia Defense 3...d5! 4. exd5 Nf6, returning the extra pawn to neutralize White's initiative.
Play Fischer's prophylactic 3...d6, taking the e5-outpost away from White's f3-knight before reinforcing f4 with ...h6 and ...g5.
Enter the uncompromising Classical 3...g5, answering 4. h4 g4 5. Ne5 with 5...Nf6 or 5...Bg7 while attacking e4 to force concrete complications.

Common Club Traps & Mistakes

Playing 3...Be7?! intending 4...Bh4+ backfires after 4. Bc4 Bh4+ 5. Kf1!, where Black's bishop is stranded offside and White wins big development time.
As White, rushing 4. Bc4 g5 5. h4?! g4 6. Ng5?! walks into 6...Nh6! followed by ...f6, trapping or repelling the premature knight while Black keeps the extra pawn.

Canonical ECO Sub-Variations

C33 King's Gambit Accepted: 1. e4 e5 2. f4 exf4 (rnbqkbnr/pppp1ppp/8/8/4Pp2/8/PPPP2PP/RNBQKBNR w KQkq -)
C34 King's Gambit Accepted: King's Knight's Gambit: 1. e4 e5 2. f4 exf4 3. Nf3 (rnbqkbnr/pppp1ppp/8/8/4Pp2/5N2/PPPP2PP/RNBQKB1R b KQkq -)
C34 King's Gambit Accepted: King's Knight's Gambit: 1. e4 e5 2. f4 exf4 3. Nf3 g5 (rnbqkbnr/pppp1p1p/8/6p1/4Pp2/5N2/PPPP2PP/RNBQKB1R w KQkq g6)
C37 King's Gambit Accepted: King's Knight's Gambit: 1. e4 e5 2. f4 exf4 3. Nf3 g5 4. Bc4 (rnbqkbnr/pppp1p1p/8/6p1/2B1Pp2/5N2/PPPP2PP/RNBQK2R b KQkq -)
C39 King's Gambit Accepted: King's Knight's Gambit: 1. e4 e5 2. f4 exf4 3. Nf3 g5 4. h4 (rnbqkbnr/pppp1p1p/8/6p1/4Pp1P/5N2/PPPP2P1/RNBQKB1R b KQkq h3)
C39 King's Gambit Accepted: Kieseritzky Gambit: 1. e4 e5 2. f4 exf4 3. Nf3 g5 4. h4 g4 5. Ne5 (rnbqkbnr/pppp1p1p/8/4N3/4PppP/8/PPPP2P1/RNBQKB1R b KQkq -)

FAQ

Why does White play 3. Nf3 before pushing 3. d4 in the King's Gambit Accepted?

Immediate 3. d4?! allows 3...Qh4+! 4. Ke2 d5!, displacing White's king and blowing open the center while White's kingside pieces are still bottled up.

Did Bobby Fischer really refute the King's Knight's Gambit with 3...d6?

Fischer's famous 1961 article proposed 3...d6 to prevent the Kieseritzky Ne5 jump, and while it stops wild romantic attacks, modern engines confirm White retains a dynamic, playable game (+0.10) via 4. d4 g5 5. h4 or 4. Bc4.

What is the easiest Grandmaster equalizer for Black against 3. Nf3?

The Modern Defense 3...d5! 4. exd5 Nf6 (or 3...Nf6 4. e5 Nh5) avoids memorizing 20-move 3...g5 forcing lines and gives Black active piece play right out of the opening.

Grandmasters Who Weaponized This Technique

Garry Kasparov (RUS · 2851 FIDE) — 13th World Champion · Master of Dynamic Initiative & Deep Prep
Bobby Fischer (USA · 2785 FIDE) — 11th World Champion · Crystal-Clear Classical Precision
José Raúl Capablanca (CUB · 8 yrs Unbeaten) — 3rd World Champion · The Human Chess Machine (8 Years Unbeaten)

C33 · King's Gambit Accepted: Bishop's Gambit & Muzio (C33) · C31 · Falkbeer Countergambit & King's Gambit Declined (C31) · C29 · Vienna Gambit: Falkbeer Defense Mainline (C29) · Bishop & Knight Checkmate (W-Maneuver)