Lopez Countergambit

The Lopez Countergambit answers the Italian-style bishop development 3. Bc4 with 3...f5, applying Philidor's idea of an early ...f5 in a position where White's bishop already eyes f7. The line is very old: it appears in the Göttingen Manuscript, and Ruy López himself played it in 1575. Its drawback is the cost in time, since Black has made only pawn moves while the a2-g8 diagonal and the kingside are loosened. Engines consider it clearly bad for Black, giving White a large advantage, though practical results on Lichess are much closer.

The most frequent reply is the quiet 4. d3, which supports e4 so that White can recapture with a pawn; after 4. d3 Black has tried unusual pawn-heavy setups such as 4...c6, while 4...Nc6 leads to unclear play. The second most common choice, 4. exf5, gives up the e-pawn and lets Black develop with 4...Bxf5, although the dark-squared bishop remains passive. The most testing move is 4. d4, which transposes to the Philidor Countergambit. After 4. d4 fxe4 5. Nxe5 the pawn cannot be regained, because 5...dxe5 6. Qh5+ g6 7. Qxe5+ wins the h8-rook; after 4. d4 exd4 White does best to prioritize development over recapturing at once. The Jaenisch Variation, 5. Ng5 Nh6 6. Nxh7, is usually reached by the Philidor Countergambit move order 3. d4 f5 4. Bc4 exd4.