Semi-Benoni

The Semi-Benoni is a form of the Old Benoni, 1. d4 c5, in which Black answers 2. d5 with 2...e5 and supports it with ...d6 after 3. e4. Capturing en passant on e6 is generally considered unwise for White, so the center freezes at once: White's pawns on d5 and e4 face Black's chain on c5, d6 and e5. Because White has not committed the c-pawn and Black has not developed the king's knight, both sides keep more flexibility than in the Czech Benoni. Black's typical ideas include an early ...f5 break and exchanging the dark-squared bishop via ...Be7-g5. White's main plans are queenside expansion or restraint, with a4 the engine's preferred move to discourage ...b5.

The most frequent continuation is 4. c4, which produces the Czech Benoni pawn structure. 4. Nc3 is almost as common and leaves the c-pawn on c2, keeping c4 free for a piece. 4. Nf3 is a less frequent alternative. Engines judge White to hold a clear advantage, but in Lichess games the results are close to even, with White scoring only slightly better.