[%c_effect c7;square;c7;type;Interesting;persistent;true] The third most popular move. The idea is to improve the pawn structure with e6-e5 at some point, maybe even on the next move.
1. e2e4  1... c7c5  2. g1f3  2... b8c6  3. f1b5  3... e7e6 This and 3...g6 are the main moves. 4. b5c6  4... b7c6  5. d2d3 