 the aforementioned Dutch Defense (2.c4 f5 or 2.Nf3 f5), French Defense (2.e4 d5), or Queen's Gambit Declined (2.c4 d5).Another possibility is 2.c4 Bb4+, the Keres Defence (also known as the Kangaroo Defence), which is fully playable, but also little independent significance, since it often transposes into the Dutch, Nimzo-Indian, or Bogo-Indian.Other important responses to 1.d4 include the Dutch (1...f5) and the Benoni Defense (1...c5).