Mason Countergambit

The Mason Countergambit, 3. d4, meets the Latvian Gambit with a counterblow in the center instead of an immediate capture. White passes over both 3. Nxe5 and 3. exf5 and leaves the e4- and d4-pawns en prise. The aim is to open lines quickly while Black's king is exposed along the weakened e8-h5 diagonal. Material is level for the moment, with four central pawns in contact and several captures available to Black.

The most frequent reply on Lichess is 3...d6. It reinforces e5 and transposes to the Philidor Countergambit, a position more often reached by 1. e4 e5 2. Nf3 d6 3. d4 f5. The engine prefers 3...fxe4, taking the e-pawn, and lists 3...Nf6 and 3...exd4 as its other main choices. In practice 3...fxe4 is the second most common move and gives Black the best results of the main replies, while 3...exd4 scores worst for Black. The engine assesses the position as a slight edge for White. Results on Lichess are close to even, and the line is generally described as sharp.