19. PxP
P-K4 was comparatively the best move, although Black’s attack would have become overwhelming after P-B4, e.g. 20. P-B3, B-B5, etc.
Diag. 159
19. … BxPch!! 20. KxB Q-R5ch 21. K-Kt1 BxP!
Emanuel Lasker won a celebrated game from Bauer (Amsterdam, 1889) with a similar sacrifice of two Bishops, and very likely this is the reason why Tarrasch’s beautiful game only earned him the second brilliancy prize at Petrograd (1914).
22. P-B3
If KxB, then Q-Kt5ch; 23. K-R1, R-Q4; 24. QxP, R-R4ch; 25. QxR, QxQch; 26. K-Kt2, Q-Kt4ch and QxKt.
22. … KR-K1
Not Q-Kt6, because of Kt-K4.