King's Gambit

Strategic Summary & Main Idea

The King's Gambit hands over a pawn on move two to open the f-file and build a centre with d4. It was the opening of the nineteenth century, and the measurement explains why it stopped being so: the position after 2.f4 measures −0.55, and none of the accepted lines improves on that — the Kieseritzky measures −0.64 and the Fischer Defence −0.80. The gambit does not lose by force: it loses because the correct defence is known. Where it still works is on the other side of the board, against players who decline it: 2...Bc5 measures +0.38 and the Falkbeer Countergambit +0.68. The f4 pawn is still a good practical bet and a bad objective one.

The pawn structure this opening produces

The King's Gambit's structural idea is clear and still correct: trading the f-pawn for a central pawn gives White a two-pawn centre, d4 and e4, against a stray black pawn on f4, and opens the f-file for the rook after castling short. The problem is the road there. While Black holds the pawn with ...g5, White cannot recover it without spending pawn moves (h4, g3) that loosen his own king — and the f-file, which was meant to be the asset, ends up pointing at an uncovered f2. That inversion is what the engine measures: in the accepted lines, the player with the unsafe king is the one who sacrificed. The structure changes completely when Black declines. In the Falkbeer, Black gives the pawn back with ...d5 and tries to use the e4 square; measured, the advance weakens more than it helps, and White ends up with the centre it wanted without paying for it. And in the modest decline with 2...Bc5, Black's bishop freezes f4 while eyeing f2, but White simply develops and gets the f-file for nothing. In short: the structure favours White in every scenario except the one where the pawn is actually taken.

Main Variations of the King's Gambit

Evaluations measured by us with Stockfish 19, depth 22, on 14/09/2026.

Frequently asked questions

Is the King's Gambit playable today?

Objectively, no: the position after 2.f4 measures −0.55, and every accepted line measured here makes that number worse. In practice it still wins games at fast time controls, because it demands correct defence from move three. The gap between those two sentences is what this catalogue measures.

What is the best defence against the King's Gambit?

The Fischer Defence with 3...d6, measuring −0.80: Black takes the pawn, gives it back when convenient and never lets White build the centre. For anyone economising on study, the Modern Defence with 3...d5 measures −0.18 and returns the pawn immediately — less advantage, almost no theory.

Is it worth declining the King's Gambit?

By the numbers, no. The two declines measured here — 2...Bc5 (+0.38) and the Falkbeer Countergambit (+0.68) — hand White the advantage the accepted gambit does not give. The f4 pawn is offered precisely because taking it is the correct answer; declining gives away for free the only argument Black has.

Guides on this opening

• An open games repertoire: meeting 1.e4 with 1...e5 without memorising Ruy Lopez theory

Common Mistakes & Where Most Amateurs Go Wrong

• 01 Sacrificing the knight in the Muzio Gambit. After 4.Bc4 g4 5.O-O gxf3 6.Qxf3 the attack is beautiful and falls short: with correct defence the position measures −3.00, and White is a whole piece down. The line: 1.e4 e5 2.f4 exf4 3.Nf3 g5 4.Bc4 g4 5.O-O gxf3 6.Qxf3 Qf6 7.e5 Qxe5 8.Bxf7+ Kxf7 9.d4 −3.00
• 02 Declining with ...d6 and trading the bishop on f3. The trade hands over the bishop pair and the f-file for nothing, and White gets everything the gambit wanted without paying the pawn: +0.37. The line: 1.e4 e5 2.f4 d6 3.Nf3 Bg4 4.fxe5 Bxf3 5.Qxf3 dxe5 6.Bc4 Qd7 7.Nc3 +0.37