Chess Opening Theory/1. d4/1...f5/2. g4

The idea of 2. g4?! is straight forward enough: deflect Black's f-pawn from control of e4, and perhaps White can get in the move e4 themselves soon, so building a strong, spacious centre with both d and e pawns. Against best play the gambit doesn't work out that way and White doesn't get complete compensation for the pawn.

2...fxg4 accepts the gambit. Though this loses control of the e4 square, it transpires that White can't make much of 3. e4?! anyway. (If 3. e4 (discovering an attack on g4 with the queen) d5 both discovers a defender of g4 in the form of the bishop and attacks e4. Black is up a pawn and better. If 4. exd5? Qxd5∓ comes with an attack on White's rook.)

The more usual move is 3. h3.

If 3...gxh3?! 4. Nxh3, White is happy to recapture while developing their pieces and an idea is to attack on the kingside with Ng5 and Qd3, e.g. 4...Nf6 5. Qd3 d5 6. Ng5 and White threatens to take three times on h7:

• 6...h6?? 7. Qg6+ Kd7 8. Nf7 forks the rook and queen, and after 8...Qe8 White has this neat manoeuvre 9. Nxh8 Qxg6 10. Nxg6+-)
• 6...g6? 7. Rxh7! and White threatens Qxg6+.
  • 7...Bf5?? and White can sacrifice their queen: 8. Rxh8! Bxd3 9. Ne6 Qd6 10. Rxf8+ (rook is defended by knight) Kd7 11. Rd8+ Kxe6 12. Rxd6+ Kxd6 13. cxd3 (retakes bishop) +- and White is up a piece.
  • 7. Rg8 and White can sacrifice their rook: 8. Rh8! Rxh8 9. Qxg6+ (drives king from defence of f7) Kd7 10. Nf7 Qe8, and White has the same manoeuvre 11. Nxh8 Qxg6 12. Nxg6
• 6...e6 is the best reply, but Black gives back the pawn and loses castling rights 7. Nxh7 Nxh7 8. Rxh7 Rxh7 9. Qg6+ Kd7 10. Qxh7.

Instead, Black is better advised to play 3...d5 and allow 4. hxg4 Bxg4=.

2....d5 declines the gambit and is also fine for Black. This allows Black's bishop to see f5, meaning that if 3. gxf5?! Black can recapture while developing their bishop, 3...Bxf5⩱. Black may still take the free pawn later, if say 3. Bg2 fxg4. 3. Qd3, threatening to take twice on f5, transposes into something called the Manhattan gambit, otherwise seen in the move order 1. d4 f5 2. Qd3 (the Alapin variation) e5 4. g4.

Other ways of defending the f-pawn are bad, e.g. 2...g6? 3. gxf5, and Black cannot take back, else 3...gxf5? 4. e4! Nf6? (thinking to prevent Qh5+; 4...fxe4?? 5. Qh5#) 5. e5! Ng4 6. h3 Nh6?! (so that Qh5+ Nf7 is possible) 7. Bxh6 Bxh6 8. Qh5+ Kf8 9. Qxh6++- etc.

2...e5?!, the Hevendehl gambit, is a surprise within a surprise.

Josef Krejcik (1885–1957) was an Austrian chess player and publisher of Wiener Schachzeitung (German: Viennese Chess Magazine).

In one of the earliest recorded games featuring the line, it was played successfully by Brian Moore against Jonathan Penrose, who would go on to become ten time British champion, in the 1955 British Chess Championship.^[1]

• Hanging Pawns, Krejcik Gambit (handle with care) · Chess Openings. (YouTube)