| offramp: There is a marvellous episode in this game which shows the high calibre of these two world champions. It starts in this posotion.
click for larger view
Material is level. All the pieces are still on the board. Black looks a little better. He now played
15...b4.
This attacks the knight on c3, but Steinitz ignored it and played the Zwischenzug
16. Nc4! This is a good move because while the Nc3 is still there the Black queen has only one available square:
16...Qc7.
click for larger view
If you have a look you'll see that the Nc3 has no square to move to! It is TRAPPED!
Steinitz sees a way out:
17. Bf4!
click for larger view
Now we see Lasker at his cleverest! The Nc3 is still trapped and attacked. All Lasker has to do is move his queen away from the the attack of the Bf3 and he can take the knight in peace.
The most obvious move is
17...Qc6, which threatens mate in one at g2.
However, that would be met by
18. Bf3 when once again the black queen would be short of squares, in fact the only square available is e8.
And after
18...Qe8, White has a square available for the knight@c3, which can now move the the square the bishop vacated:
19. Ne2!=
click for larger viewWell, Lasker saw that and clearly thought his position was worth more than =. He had a really outstanding idea.
When his queen was threatened after
17. Bf4, he played 17...e5!
click for larger view
It's a pawn sacrifice with a very specific idea.
After
18. Bxe5 Qc6
19. Bf3 <as before!>. But Black now plays
19...Qe6! Instead of ...Qe8. Lasker makes use of the square vacated by the e-pawn. It is much more aggressive.
click for larger view
Now both white knights are attacked. If the Nc4 moves then the Be5 is loose. The whole position is tense and Steinitz deserves great credit for finding a clear path through the complications. | 
Kibitzing
