Play by both sides has been logical and good up to this point: the position is equal.
1. c2c4  1... e7e5  2. b1c3  2... g8f6  3. g1f3  3... b8c6  4. g2g3  4... d7d5  5. c4d5  5... f6d5  6. f1g2  6... f8c5 One of the main lines of the modern way of playing the English Opening. 7. d2d3  7... e8g8  8. c1d2 This is a thematic move, but rarely played before castling. 8... d5f6 With the bishop on c5 the knight usually goes to f6, which must be followed at some point by the move h6, to prevent Bg5. This is Black's ideal development, with the knight close to the king and the bishop on a good diagonal. 9. a2a3 Preparing b4 and inducing Black to play a5, which weakens the b5-square and gives some additional possibilities for White. This move is actually a theoretical novelty—while the position still has a rather thematic character, with well-known plans, this position specifically has never been played before. 9... h7h6 [%c_effect h6;square;h6;type;GreatFind;persistent;true] More accurate than 9...a5, which gives White some hope for a slight advantage. 10. b2b4  10... c5d6  11. e1g1  11... a7a6 This move is important to prevent b4-b5. 12. d2c1 A difficult move to play, but easy to explain: White wants to place the bishop on b2, on its best diagonal, at the same time freeing the d2-square for a knight maneuver. Of course, there are several alternatives, but none of them offer an advantage. 12... c8f5  13. c1b2  13... d8d7 Developing and preparing to exchange the dangerous light-squared bishop on g2 with Bh3. 14. c3a4  14... f5h3  15. a1c1  15... a8d8  16. d1c2  16... f8e8  17. f1d1  17... h3g2 