A difficult move. The idea is to play …g7-g6 without White having check on h6 and also move it to h4, restricting the development of White's queen on h1. But perhaps it would be better to fight for the center first.
1. c2c4 A natural opening move, but it's hard to say if it's better than the more restrained pawn advance to c3. 1.Nb3 and 1.d4 are good moves as well. 1... c7c6 This is more accurate than copying White's first move. 2. d2d4 