6.  QxP QxQ

Compulsory.  If B-K3 instead, 7.  B-B4 attacks QB7.  B-Q3 in reply to that would be inferior.  By exchanging Bishops White would render the Black QP “backward,” and on the open file its capture would be inevitable.

7.  KtxQ         B-Q3
8.  Kt-QB3       Kt-K2

Black prepares to castle on the King’s side.  It is more usual, and probably stronger, to castle on the Queen’s side, as the King then protects the QBP, which in the present case would be weak if Black’s KB were to be exchanged.

9.   Castles       Castles.
10.   P-B4          R-K1

---------------------------------------
8 | #R |    | #B |    | #R |    | #K |    |
|---------------------------------------|
7 |    | #P | #P |    | #Kt| #P | #P | #P |
|---------------------------------------|
6 | #P |    | #P | #B |    |    |    |    |
|---------------------------------------|
5 |    |    |    |    |    |    |    |    |
|---------------------------------------|
4 |    |    |    | ^Kt| ^P | ^P |    |    |
|---------------------------------------|
3 |    |    | ^Kt|    |    |    |    |    |
|---------------------------------------|
2 | ^P | ^P | ^P |    |    |    | ^P | ^P |
|---------------------------------------|
1 | ^R |    | ^B |    |    | ^R | ^K |    |
---------------------------------------
A    B    C    D    E    F    G    H

Diag. 126

Black allows his opponent too much latitude on the King’s wing.  He should prevent White’s P-B5, which obstructs his QB, by P-KB4.  After P-K5 the game would be equalised by B-B4, BxKt, and B-K3.

A draw would then be practically certain, with the Bishops of opposite colours.  Black probably thought White would not risk weakening his KP by P-B5.  But with unfailing judgment Lasker foresees that, in consequence of the greater mobility of his pieces, his attack will be successful before a counter attack on the weak KP can be instituted.

          11.  Kt-Kt3 P-B3

Even now P-KB4 was imperative, though it would keep the Bishop from that square.  The continuation could have been 12.  P-K5, B-Kt5; 13.  Kt-K2 (or R4), Kt-Q4, and the Bishop is safe.

          12.  P-B5!!

This move has a twofold aim.  It shuts in the Bishop, and allows B-B4, exchanging the Black QB.

          12. ...  P-QKt3

The diagonal QR1-KR8 is the only one in which the Bishop has any prospects of action.  However, as soon as he relinquishes his present diagonal, a White Knight settles at K6 and the Black Rooks are very much hampered.

          13.  B-B4 B-Kt2

Black should have exchanged the Bishops.  Now he gets a weak pawn at Q3.  Before playing B-Kt2, P-B4 should be played to prevent the Knight getting from Kt3-Q4-K6.

14.  BxB PxB 15.  Kt-Q4 QR-Q1 16.  Kt-K6 R-Q2 17.  QR-Q1 Kt-B1 18.  R-B2 P-QKt4 19.  KR-Q2

This holds Black’s Kt at B1.  White’s next move prevents the Bishop getting into action by P-B4.  After depriving all the Black pieces of their mobility, White turns his attention to a determined assault on the Black King.