William Steinitz vs Georg Marco

In this position , its white to move. White’s knight has a nice square on e5 but Black is ready to kick it with …f6 and …e5. Black’s bishop will get some fresh air and White would lose the advantage.

Steinitz found the right idea because more natural options would give Black a reasonable position. So his creating an outpost maneuver can be considered as prophylaxis. And it was possible only because of the weakness of the d6-square.
Please click on the First Move to watch the game …