10. … KtxKt
Not PxKt, on account of BxP.
11. PxKt P-QB4 12. RPxP B-K2
in order to castle in reply to B-R4.
13. Q-B3
Here White should have got back his second pawn by PxQP. If then 13. … P-B5; 14. B-R4, Castles; 15. PxP, BxP, White plays P-QB3, providing a retreat for his R or B. After the move in the text this manœuvre becomes impossible, because the B after P-B3 can be attacked twice but has lost the support of the Queen.
13. … B-K3 14. RxP Castles 15. PxP P-B5 16. B-R2
Now the Bishop is hemmed in permanently; in other words, Black is a piece up and must win easily. Therefore 16. B-R4 was compulsory in order to get at any rate three pawns for the piece, thus: 16. … B-Q2; 17. QxP, RxR; 18. PxR, BxB; 19. QxP.
16. … RxR 17. PxR Q-R4 18. B-Kt1 P-B6 19. Q-Kt3
White tries to work up an attack on the King’s side while Black is still occupied on the other wing.