Philidor Countergambit

The Philidor Countergambit is a reply to the Fyfe Gambit, 3. d4, in the Max Lange Defense of the Vienna Game. Instead of exchanging on d4, Black hits e4 with 3...f5, leaving the f-pawn en prise and loosening the kingside. The engine rates White clearly better and prefers 4. exf5. In practice 4. d5, gaining space and driving the knight away, is the most common answer, followed by 4. dxe5. The line is rarely seen.