White has to capture with the B, in order to exchange the Black Knight if it should play to B4.  After 13.  KtxKt, B-Q5ch; 14.  K-R1, Kt-B4; White’s Knight would not be able to move from K4 on account of the threat:  Kt-Kt6ch.  Sooner or later, Black would get a deciding advantage by enforcing the exchange of White’s Knight, e.g. 15.  Q-K1, Q-K2; 16.  R-QKt1, B-Q2; 17.  P-QKt3, Castles QR; 18.  B-Kt2, QxKt; 19.  BxQ, Kt-Kt6ch; 20.  QxKt, PxQ; 21.  P-KR3, BxP; 22.  PxB, RxPch; 23.  K-Kt2, R-R7ch; 24.  KxP, RxB; or 21.  BxB, RxPch, followed by PxB and QR-R1.

13. ...        B-Q5ch
14.  K-R1      Kt-B4
15.  BxKt      BxB

White is helpless against the two powerful Bishops.

          16.  R-K1ch K-B1

Black forfeits his chance of castling, not a great loss under the circumstances.  In any case his KR is needed on the Rook’s file, and Black would only have castled on the Queen’s side if at all.

          17.  Q-B3

Here P-KR3 was essential in order to prevent the further advance of the KRP.  The weakness at Kt3 would not have been so serious in the absence of a Black Knight.  Now Black forces the advance of White’s KKtP, and the Bishops become immediately effective.

          17. ...  P-R6
          18.  P-KKt3

not P-KKt4 on account of Q-R5.

          18. ...  Q-Q2
          19.  B-Q2 B-Kt5
          20.  Q-B1

If Q-Q3, Black plays Q-B4 and White cannot exchange Queens because of B-B6 mate.

          20. ...  Q-B4

threatening Q-B7.

21.  QR-B1     K-Kt2
22.  B-K3      B-B3

Black must not exchange his valuable Bishop.

          23.  P-Kt3 KR-K1
          24.  B-B2

There is no answer to Black’s threat of doubling the Rooks on the K file.  If White plays Q-B2, Black’s Queen effects an entry at Q6, after which he would double his Rooks, and White’s Bishop cannot be defended.  After the text move, Black forces the exchange of his two Rooks for the Queen.  Generally speaking, this is no disadvantage, but in consequence of the exposed position of the White King, it means a speedy loss for White.

24. ...  B-B6ch 25.  K-Kt1 B-Kt7 26.  RxR BxQ 27.  RxR Q-Q6!

If now RxB Black plays Q-B6.

28.  R-K8

In order to play R-K3 if Black plays BxKt.

28. ...  Q-B6!
29.  KxB Q-R8ch
30.  B-Kt1 Q-Kt7ch
31.  K-K1 QxBch
32.  K-Q2 QxPch

        Resigns

for the pawn queens.

Game no. 46

White:  G. A. Thomas.  Black:  Ed. Lasker.

Irregular Opening (compare Game No. 45).

1.  P-Q4 P-QB4 2.  P-Q5 P-Q3 3.  P-QB4 P-KKt3 4.  Kt-QB3 B-Kt2 5.  B-Q2

This is not necessary.  Black could hardly exchange his B for the Kt; the weakness at his KB3 and KR3 would become too serious a disadvantage.