Anti-Philidor, Lion's Cave

The Lion's Cave is Black's standard reply to the Anti-Philidor. The move 4...e5 confronts White's d4-e4-f4 center at once, even though the e5-pawn is now attacked twice. Because White's f-pawn has already advanced, the Philidor-type structure Black wants cannot be kept intact. The central tension has to be resolved soon, usually on White's terms. The engine gives White a slight edge. Black's practical results are still respectable, and decisive games dominate, with very few draws.

The most common continuation is 5. Nf3. Black is then obliged to play 5...exd4, since 5...Be7 loses a pawn to 6. fxe5 dxe5 7. dxe5. After 6. Qxd4, Black can choose the Lion Claw Gambit, 6...c6 7. Bc4 d5. This strikes at e4 with the d-pawn at the cost of material, aiming at White's centralized queen and the kingside White loosened with f4. White's main alternatives are the immediate captures 5. fxe5 and 5. dxe5, which clear the center straight away and avoid the gambit lines.