Benoni Defense

The Benoni Defense arises after 1. d4 Nf6 2. c4 c5, where Black challenges the d4-pawn with the c-pawn instead of contesting the center with ...d5. The name traces back to Aaron Reinganum's 1825 book Ben-Oni, whose Hebrew title means "son of my sorrow"; the label later attached itself to 1. d4 c5 and then to this position. The c5-pawn cannot simply be taken: after 3. dxc5 e6 Black regains it with ...Bxc5, having removed a central pawn. Protecting d4 also concedes something. 3. Nf3 transposes to the Anti-Benoni line of the Symmetrical English, and 3. e3 cxd4 4. exd4 d5 5. Nc3 leads to a Caro-Kann Panov Attack structure.

The usual reply, chosen in roughly three games out of five, is 3. d5, gaining space and fixing a wedge in Black's camp. Black then decides how to attack the pawn chain. 3...e6 is the Modern Variation; 3...b5 is the Benko Gambit; 3...e5 is the Czech Benoni; and 3...d6, the Hromádka System, or 3...g6 tend to transpose into main lines or the King's Indian Defense.

In the Modern Benoni Black exchanges with ...exd5, giving White a central majority while acquiring a queenside majority whose advance is backed by a bishop on g7. After 4. Nc3 exd5 5. cxd5 d6 the King's Pawn Line 6. e4 g6 is the most direct test. The Pawn Storm Variation 7. f4 aims for e4-e5, and 7...Bg7 8. Nf3 O-O reaches the Four Pawns Attack, while the Classical Variation 7. Nf3 is calmer. White can also fianchetto with 6. Nf3 g6 7. g3. The Snake Benoni, 5...Bd6, sends the bishop to d6 rather than g7.

The Czech Benoni locks the center with ...e5 and is steadier but more passive: play revolves around maneuvering, with Black preparing ...b5 or ...f5 and White often expanding with h3 and g4 to stop the latter. The Benko Gambit, 3...b5 4. cxb5 a6 5. bxa6 Bxa6, gives up a pawn for open queenside files and lasting pressure along them.

Engines give White a slight edge after 2...c5, yet in Lichess games Black scores marginally better than White, reflecting how readily the resulting positions become unbalanced. Saint Amant played 1...c5 against Staunton in their 1843 match, and Alekhine won a game with the Old Benoni, 1. d4 c5, against Bogoljubow in 1934.