Winning With a Retreat

In a game of speed chess, I retreated my knight to win a piece.  My opponent, Chog81 of Argentina, could not save his piece.  I played white.  Here are the moves of the games along with my commentary:

1. e4 e5
2. Nf3 Nc6
3. Bc4 h6

Black prevents Ng5.

4. h3 Nf6
5. 0-0 Bc5
6. c3 d6
7. d4 exd
8. cxd Bb6

I have a strong pawn centre.

9. Nc3 Bd7
10. e5 dxe
11. dxe Nh5

The knight is out of position on h5.  Ng8 is necessary.

12. Re1 0-0
13. Nh2 Qc8

The knight is trapped.

14. Qxh5 Nd5

The black knight threatens to fork my rooks on c2.

15. Bb3 Be6

I can prevent the knight fork with Bd1, but I decide to play more actively.

16. Ng4 Bxb3
17. axb3 Nc2

The black knight forks my rooks.

18. Nxh6 gxh6

I sacrifice my knight to destroy the pawn shield around the black king.

19. Bxh6 Bxf2+

The check is not dangerous.

20. Kxf2 Nxe1
21. Qg5+

Black resigns because I have mate in one.  The black king must move to h8 or h7.  I then mate with Qg7 on my following move.

Retreats are often defensive moves, but they can also be used to attack.  My thirteenth move, Nh2, is not a defensive move.  It creates a discovered attack on the black knight.  On black's eleventh move, Ng8, a retreat of the knight to the back rank, is the only move that saves the piece.  Though the move is purely defensive and makes it difficult for the knight to take part in the game, it is better than Nh5.