The idea of this move is to avoid Bg5.
1. c2c4  1... e7e5  2. b1c3  2... g8f6  3. g1f3  3... b8c6  4. e2e4 This is currently a fashionable variation of the English Four Knights Opening. It's curious that I have become a sort of \"specialist\" in this line, although I have never played it in an official over-the-board game. But times have changed, and when searching in an online database, I found no fewer than 16 of my own games, all played in Titled Tuesdays. Of course, the reader can find more qualified players to follow in case they decide to study this variation, but I must say my score is not bad at all. Given my poor Titled Tuesday record, this shows that this line must be really very good for White. 4... f8c5  5. f3e5 This is the point; otherwise, Black has very comfortable play. 5... c6e5  6. d2d4  6... c5b4  7. d4e5  7... f6e4 Now White has a difficult decision between 8.Qd4 and 8.Qf3. To me, it's not clear which is better, but the latter is more popular these days. 8. d1f3  8... e4c3  9. b2c3  9... b4a5  10. c1f4  10... e8g8  11. e1c1 It looks crazy for the untrained (or unprepared) eye to direct the king toward such a scattered pawn structure. But if the computers say it's good, we have to study it. More conservative (or lazier) players might consider 11.Rd1 or 11.Be2 and castling short. 11... d8e7  12. c1b2 This is necessary to avoid a queen invasion. 12... a8b8 An excellent move, creating an x-ray with the king and getting ready for counterplay with b7-b5. This is still mainstream opening theory. 13. f3e3 A strong prophylactic move. White gets ready to meet 13...b5 with 14.c5. If White manages to stop Black's counterplay on the queenside, then he is ready for a devastating kingside attack. Let's not forget that Black's king is completely abandoned by his pieces. When the bishop gets to d3, checkmate is going to be a real possibility. 13... b7b6 This is a new and strange move. Black's counterplay is usually connected with b7-b5, so why advance this move only one square $2 14. f1d3  14... e7e6  15. e3g3 Not the most accurate. I think 15.Qe4 or 15.h4 is better.