Blumenfeld Countergambit: Spielmann Variation

The Blumenfeld Countergambit: Spielmann Variation is a chess opening classified under ECO code E10 in the Indian Defences family, where Black responds to 1.d4 with 1...Nf6, including the Nimzo-Indian, Queen's Indian, and King's Indian. It is reached after 6 moves: 1. d4 Nf6 2. c4 e6 3. Nf3 c5 4. d5 b5 5. Bg5 exd5 6. cxd5 h6. The resulting position leaves white to move.