The Benoni Defense is a chess opening characterized by an early reply of ...c5 against White's opening move 1.d4. Most commonly, it is reached by the sequence: 1. d4 Nf62. c4 c53. d5 Black can then sacrifice a pawn with 3...b5 (the Benko Gambit), otherwise 3...e6 is the most common move (although 3...d6 or 3...g6 are also seen, typically transposing to main lines). The Old Benoni Defense is characterized by 1. d4 c5 This will usually transpose into a main line after 2.d5, but Black has other options such as an early ...f5.