Duplication

One of the oddities of chess is that it is entirely possible to give a good effort, win an interesting game... and then find out that it has all been played before. This is pretty much what happened to me this morning, in an Internet blitz game against a player whose rating was very close to my own. When a tactical opportunity presented itself I had to think for a minute before responding but it was time well spent because the game was soon over.

I have the White pieces.
1.d4 d5 2.c4 Nc6 3.Nf3 Nf6?!
Stronger is the main line move 3...Bg4.
4.cxd5 Nxd5 5.e4 Nf6 6.Nc3 Bg4 7.d5
Black has already gone wrong and here he should try to dig in with 7...Bxf3 8.gxf3 Ne5. But White keeps an advantage with 9.f4 Ned7 10.e5 Ng8 and now 11.Qb3 seems best. Instead of this Black plays a tempting but unsound move whose only merit is increasing the pressure on f3.
7...Ne5? (diagram)
White to play and win!
8.Nxe5! Bxd1 9.Bb5+ c6 10.dxc6
White now threatens both 11.cxb7+ and 11.c7+ followed by liquidation on d7 and a recapture on d1. Black has a whole tempo to work with but cannot prevent the loss of at least a piece.
10...bxc6
This loses quickly. The alternatives are:
a) 10...a6 11.c7+ axb5 12.cxd8Q+ Rxd8 13.Nxd1 with an extra piece for White;
b) 10...Bg4 and now:
i) 11.c7+?! Qd7! (stronger than 11...Bd7?! 12.cxd8+ Rxd8 13.Nxd7 Nxd7 14.0-0 e6 15.Rd1 Be7 16.Bf4 a6 17.Ba4 b5 18.Nxb5! axb5 19.Bxb5 f6 20.Rxd7 Rxd7 21.Rd1 and Black resigned in Zimlich-Baumgardt, German League 1996/97) 12.Nxd7 Bxd7 13.Bf4. Here White is only a pawn up but should still win eventually;
ii) 11.cxb7+ Bd7 12.Nxd7 Nxd7 13.bxa8Q Qxa8 14.0-0 and Black cannot prevent 15.Rd1, which will leave White with three pieces against Black's queen;
iii) 11.Nxg4! bxc6 12.Bxc6+ Nd7 13.Ne5 e6 14.Bxd7+ and White finishes a piece ahead after either 14...Qxd7 or 14...Ke7 15.Nc6+.
11.Bxc6+ Nd7 12.Bxd7+ Qxd7 13.Nxd7 Kxd7 14.Nxd1
Black resigned.
1-0