Moves 1-6 as in Game No. 16.

1. 6…exd4 Compare note to move No. 6 in Game 14.
2. 8…Bd6 This is the key to the variation. Black threatens to obtain a draw by perpetual check through BxPch, followed by Q-R5ch and QxPch. This is not good enough against a weaker opponent in a tournament, and a strong player cannot afford to play the Riga defence. But that is not a point against the variation. To prove it unsound, White has to find a win.
3. 10.Kh1 After 10. K-B1 Black has a tremendous attack, and drives it home before White can manage to bring his extra piece into play. A game Maroczy-Berger (Vienna, 1908) is an illustration of this.
4. 10…Qh4 It now looks as if White were lost. But a fine sacrifice forces the exchange of all Black’s attacking pieces, and saves the situation.
5. 14…Be6 After the terrible slaughter, the position is somewhat clearer. Black has a Rook and two pawns for two minor pieces, a slight advantage for the end-game, but as yet there is no thought of an end-game. White, in possession of two Bishops, with an open Queen’s file on which the Black King stands, has good attacking chances, and most masters would think the position favourable for White. P-KB4 is a plausible move, but is followed by a pretty mate by 15. B-Kt5. The move in the text threatens to eliminate the KB by P-QB4, P-QKt4.
6. 17.g4 Tarrasch recommends 17. R-Q1, threatening Kt-Q5ch. If P-B3, White could play 18. B-Kt6, thereby permanently preventing Black from contesting the Queen’s file, and then try to exchange Black’s B by Kt-K2-Q4. With two Bishops, White would then have winning chances. A subtle idea underlies White’s move of P-KKt4. He wishes to take advantage of the fact that Black has exchanged the KB by playing P-Kt5, thus holding all the four pawns on the King’s side. But Black finds a surprising reply, which seems to refute White’s plan. Capablanca played against Ed. Lasker (New York, 1915), 17. P-KKt4, P-KKt3; 18. K-Kt3, P-KR4; 19. PxBP, P-R5ch; 20. K-R2, PxP; 21. Kt-K2, P-Kt4; 22. B-Kt3, BxB; 23. RPxB, KR-KKt1; 24. R-Q1, QR-Q1; 25. RxR, KxR; 26. Kt-K4, winning a pawn.
7. 18…Rag8 Black offers the exchange in order to get rid of White’s QB. If White accepts the sacrifice, he loses his KKtP, and Black retains three passed pawns for the piece, at least an equivalent for the end-game. White should decline the doubtful gift and meet the threat of P-R3 and P-KKt4 with 19. R-KKt1.
8. 22.Rd1 in order to play 23. B-Q7 in answer to P-B4. This explains White’s check at move 20.
9. 23…Kf6 If now 24. Kt-Q5ch, Black would assail the White King with K-K4; 25. KtxP, B-B5-K7-B6. The Black phalanx of pawns becomes menacing.
10. 26…Rh7 Black need no longer fear to exchange Rooks, for he would then threaten the Queen’s side pawns with his King whilst the passed pawns kept the White forces occupied.
11. 29…c6 The aim of this move is not clear. Black should adopt a forward policy with P-Kt5, P-B5, R-R2, etc.
12. 31.Rh8 Now none of the pawns can advance: P-B5 would be answered by 32. R-K8, R-K2; 33. RxR, KxR; 34. Kt-Kt3 and one of the pawns is lost.
13. 40.Rd1 White tries to win at all costs--and loses. By a forcible advance on the Queen’s side, he creates new chances, but also new weaknesses.
14. 44.f3 PxP fails on account of P-B6ch and R-R2.
15. 46.b5 Too late.
16. 54…a5 The RP cannot be prevented from pushing on to R6, after which a mate is threatened by the Black Rook on the eighth rank. R-Q1 would then be compulsory. But that lets the Black Rook in on the seventh (KR-R7, followed by P-B7ch).