Wing Gambit, Marshall Variation

The Marshall Variation is the most frequent continuation of the Wing Gambit. With 3. a3 White offers to trade the a-pawn for the intruder on b4. After 3...bxa3, the Carlsbad Variation, the recapture Bxa3 develops the dark-squared bishop onto an active diagonal and leaves the a- and b-files open for White's heavy pieces, which is the compensation White is aiming for. Black takes on a3 in roughly half of the games, and White scores well in that branch in online play.

The critical answer is 3...d5, which declines the second pawn and strikes at e4 before White can establish a pawn on d4. White's best reply is 4. exd5, and 4...Qxd5 5. Bb2 is the Marienbad Variation, in which Black keeps the extra pawn and has a centralized queen. Theory holds that Black stands better after 3...d5, and Black's practical results in that line are stronger than after the capture on a3. The quieter 3...e6, preparing ...d5 with pawn support, is the second most popular reply. The engine assesses the position after 3. a3 as a slight advantage for Black.