The following position arose from a blitz chess game played on the Internet Chess Club this afternoon. I am white, and black is to move.

As you can see, material is even; white has all his pieces but the Rd1 trained against the enemy kings' shelter, a strong knight on f6, and is threatening to win an exchange with Nxe8 -however good or bad that move may be, given the strength of the knight in the game position.