King's Gambit

The King's Gambit, 1. e4 e5 2. f4, offers the f-pawn to lure Black's e-pawn away from d4, so that White can later build a full center with d4 and, once castled, place a rook on the half-open f-file. The cost is structural. Advancing the f-pawn before castling loosens the e1-h4 and a7-g1 diagonals around White's king. Because of this, fxe5 is not yet a real threat, since ...Qh4+ would follow. Black therefore need not defend e5 at once, while 2...Qh4+ 3. g3 only forces the queen back.

Accepting with 2...exf4 is the most frequent reply and is generally regarded as the most testing. White cannot play 3. d4 immediately because of 3...Qh4+, so 3. Nf3, the King's Knight's Gambit, is the usual way to cover h4. The main alternative is 3. Bc4, the Bishop's Gambit, which allows the check in return for gaining time on the queen after Kf1 and Nf3. After 3. Nf3, Black chooses between holding the pawn and giving it back. The first approach starts with 3...g5, which leads to the Kieseritzky Gambit (4. h4 g4 5. Ne5), the Muzio Gambit (4. Bc4 g4 5. O-O, sacrificing the knight), the unsound Allgaier (4. h4 g4 5. Ng5) or the Quaade Gambit (4. Nc3). Other ways to keep the pawn are the Fischer Defense, 3...d6, and the Becker Defense, 3...h6. The second approach is the Modern Defense, 3...d5, which returns the pawn for free development.

Among the ways to decline, the Falkbeer Countergambit, 2...d5, is the principal modern choice. In its main line, 3. exd5 exf4 4. Nf3 Nf6, Black takes on f4 anyway but aims for activity rather than material. The Classical Variation, 2...Bc5, is a calmer option and sets a trap: 3. fxe5?? Qh4+ 4. g3 Qxe4+ wins the h1-rook. The Queen's Knight Defense, 2...Nc6, is very common in amateur play, and 2...d6 is also frequent. Rarer tries such as 2...f5, 2...Qf6 and 2...c5 have a dubious reputation.

The opening appears in Lucena's 1497 treatise and was the dominant line of the Romantic era. Anderssen used it in the Immortal Game of 1851. Its standing declined as defensive technique improved and as Steinitz and later the positional and hypermodern schools dismissed it. Fischer's article "A Bust to the King's Gambit", written after his loss to Spassky in a Kieseritzky at Mar del Plata in 1960, claimed a forced win for Black. Alekhine, Keres, Tal, Spassky and the Polgár sisters have still played it on occasion. It is rare at elite level, where a well-prepared Black is thought to neutralize it. The engine gives Black a slight edge, but White scores well in online games, and the opening remains popular at club level and in faster time controls.