So what did black miss?

[Richard Cribb]

This game was played in the 1964 chess olympiad in Tel Aviv:

Andrzej Filipowicz - Florin Gheorghiu
1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 a6 5. c4 Nf6 6. Nc3 Qc7 7. Bd3 Nc6 8. Nc2
Ne5 9. Qe2 d6 10. O-O Bd7 11. f4 Nxd3 12. Qxd3 Rc8 13. Ne3 Be7 14. Kh1 Bc6 15.
b3 O-O 16. Bb2 b5 17. Ncd5 bxc4 18. Nxe7+ Qxe7 19. Bxf6 Qxf6 20. bxc4 Rb8 21.
Rac1 Rb2 22. Rc2 Rbb8 23. Rcc1 Rb2 24. Rc2 Rbb8 1/2-1/2

Looks like a trivial draw, but in fact black missed a great opportunity to get a decisive advantage in the opening.
Now, can you find what the strong grandmaster overlooked?

 

[punkbass2000]

No, I can't I've looked at this for a while and don't see too much, but then, the Najdorf is complex and I'm not particularly familiar with it.

 

[Richard Cribb]

No, I can't I've looked at this for a while and don't see too much, but then, the Najdorf is complex and I'm not particularly familiar with it.

Firstly allow me some nitpicking. This is not a Najdorf. The Najdorf-variation goes 1e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5. Nc3 a6. However I understand that one gets a bit confused by all those Sicilian variations. This one is rather a Paulsen or a Kan.
So to the game. In chess we usually talk about two sort of weaknesses, static and dynamic. A static weakness is usually a defect in the pawn structure, like an isolated pawn, a doubled pawn, a hole etc, and they are there two stay, the way of exploiting them is methodical, you have time.
Dynamic weaknesses however, are usually associated with the positioning of the pieces. Like your opponent moves a key piece in defence allowing you to sacrifice at h7. In those occasions you must strike when the iron is hot. Like here.
The solution is the rather surprising 9...Qc7-d6! At first this looks like a beginner's move; you move your queen for the second time in the opening while blocking your own development. Yet the move is strong, since it exploits the dynamic weakness in white's camp, the bishop at d3. It has nowhere to go, and the only way to guard it is quite miserable; 10.Kd2 and now black just picks up a pawn:10...Nxc4+ and on any of white king moves returns the knight to e5. The verdict of the position should be a win for black, extra pawn and a safer king.
From this example we can learn:
Routine play in the opening can be dangerous. Always look out for tactics.
Dynamical weaknesses must be exploited at once. In this game, black only had this one chance before white could successfully regroup.
Strong players also make elementary mistakes.
I apologize if some people found this example dull and disappointing, no fancy mates or tactical fireworks, but personally I find it amusing, and this sort of things can really improve ones tactical alertness.
I will try to post some more sizzling stuff later...