The Blumenfeld Countergambit is a chess opening characterised by the moves 3...e6 4.Nf3 b5 in the Benoni Defense arising after: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nf3 b5 or alternatively: 1. d4 Nf6 2. c4 e6 3. Nf3 c5 4. d5 b5 In fact, as many as 30... Wikipedia