Semi-Slav Defense: Anti-Noteboom, Stonewall Variation, Portisch Gambit

The Semi-Slav Defense: Anti-Noteboom, Stonewall Variation, Portisch Gambit is a chess opening classified under ECO code D31 in the Closed & Semi-Closed Games family, arising from 1.d4 d5, including the Queen's Gambit, Slav Defense, and related systems. It is reached after 5 moves: 1. d4 d5 2. c4 e6 3. Nc3 c6 4. e3 f5 5. g4. The resulting position leaves black to move.