Superior Mobility

In chess sometimes sacrifices have to be made in order to gain rapid development and attain an attacking position.  In the posted game, an attack ostensibly aimed at Black's queenside suddenly turns into an attack on the other wing.  The explanation:  superior mobility.

E. LASKER vs. WINKELMAN
New York, 1926

Queen's Gambit Declined

1. Nf3, Nf6
2. d4, d5
3. c4, e6
4. Bg5, Nbd7
5. e3, Be7
6. Nc3, 0-0
7. Bd3, a6

Stronger is 7....c5, allowing Black to equalize.

8. Ne5!, dxc4
9. Nxc4, b5??

This move drives White's Knight to a5 where it will make inroads to Black's position.

10. Na5!, c5
11. Nc6, Qe8
12. Qf3!! ....

Now, White threatens to win a Rook with 13. Nxe7 and 14. Qxa8.

12. .... Nb6

Protecting the Rook. If 12....Bb7, White still wins a piece by 13. Nxe7.

13. Ne4! ....

Black cannot take the c6 Knight because of 14. Nxf6 winning the Queen.

An interesting situation develops after 13....Bb7, 14. Nxe7+ Qxe7, 15. Nxf6+ gxf6, 16. Qh5 with Black losing its Queen as 16. ...f5 is the only way to avoid mate.

13. .... Nfd5

Black's position deteriorates. But 13....Nxe4, 14. Nxe7+ Kh8, 15. Bxe4 would leave White in tremendous material advantage.  At this point, saving the Rook is not a solution. For if 15....Ra7, 16. Bxh7 Rxe7 (not 16....Kxh7, 17. Qh5 mate), 17. Qh5...., White wins with a mating attack.

14. Nxe7+, Nxe7
15. Nf6+, Resigns

An elegant finish.  The subsequent moves would have been 15....gxf6, 16. Bxh7+ Kxh7 (If 16....Kg7, then 17. Qxf6+), 17. Qh5+ Kg7, 18. Qh6+ Kg8, 19. Bxf6 Ng6, 20. Qg7 mate.