Biel Interzonal 1976, round 18, next to last,
position after White's 35. move:
2r5/PP2R1PK/3n2NP/5P2/1Q1B1p2/6p1/6bp/5q1k b

The moves up to this point had been:

[Event "Biel Interzonal"]
[Site "Biel"]
[Date "1976.08.04"]
[Round "18"]
[White "Huebner, Robert"]
[Black "Petrosian, Tigran V"]
[Result "0-1"]
[ECO "B06"]
[WhiteElo "2585"]
[BlackElo "2635"]

1. Nf3 g6 2. e4 Bg7 3. d4 d6 4. Bc4 e6 5. Bb3 Ne7 6. O-O O-O 7. c3 b6 8.
Nbd2
Nbc6 9. Re1 Na5 10. Bc2 c5 11. Nf1 Nac6 12. Be3 Qc7 13. Rc1 e5 14. h3 Nd8
15.
N3h2 Bb7 16. Ng3 exd4 17. cxd4 Ne6 18. Bb3 d5 19. e5 Nc6 20. Ng4 Rfd8 21.
dxc5
bxc5 22. Bxc5 Nxc5 23. Rxc5 Qe7 24. Qc1 Rac8 25. Nf6+ Kh8 26. Nxd5 Qf8 27.
Qe3
Nxe5 28. Rxc8 Rxc8 29. Qxa7 Bxd5 30. Bxd5 Qb4 31. Re2 f5 32. Qb7 Rc1+ 33.
Kh2
Qf8 34. f4 Nd3 35. Qb5

Black has about 5 min in the clock, White about 15.

At this point Black is completely lost. However, his next
move is a surprise that looks like a real tactical threat for about 2
seconds. Petrosian's entire demeanor, when making this move
said:"Now I have won."

35. -- Bd4

What the audience didn't know is that the real game wasn't being played
on the chess board at all. The story, can be verified
from the original KGB documents*.

Huebner, had been warned by the Soviets, who were
trying to maximize the chances of their vastly overrated
contingent: Petrosian, Tal, Smyslov - all of them over the
hill. So he knows he cannot risk beating Petrosian: in a number
of calls from the Embassy of the USSR in Berne Abelard
was mentioned. Therefore, Huebner looks for the most
passive move that eliminates the spurious threats:

36. Nh1

Great square for a Knight when you must not win -
and objectively possibly the best move.

36. -- Qd6

Petrosian strengthens his attack. Now white can win
the Q or mate in in 4 (37. Qe8 etc), but Petrosian
knows that Huebner knows what they will do to
him if he wins, and that's why Huebner plays

37. g3

And that does it (37. Kg7). White's advantage is gone, but so
are his worries about dire consequences.

37 -- Nxf4

But what is this? Petrolium doesn't want the present!
The reason is this: he was just passed a note, hidden
in a Yoghurt cup, that reminded him that Allen Dulles'
organization still resided at Spiegelgasse 14 in
Zurich and that they were watching live on closed
circuit TV, relayed through Langley, VA.

Huebner immediately understands what has
happened, and for a second thinks that he has
protection in McLean, and therefore plays

38. Qe8+

which is not dreadful, but there isn't any mate
any more.

38. -- Kg7 39. Re7+ Kh6

Bang. Suddenly it occurred to Huebner that neither
the ghost of Allen Dulles, nor the spooks in McLean
have the slightest interest in him. Now he is losing
the game but his kneecaps will not be broken and
his balls will not be cut off.

40. Nf2 Bxf2 41. Rxh7 Kg5 0-1

So Petrosian seems to have won the game but
he was not with us much longer. He died when he
was 55 and in 200 years when the archives in
McLean, VA, will be opened we will find out how
he was done in.

Coming soon: Interpretation of Castro - Petrosian, Biel 1976