Tigran Petrosian vs Boris Spassky · World Championship Match, Game 10, Moscow, 1966 · King's Indian / Fianchetto · 1–0
23… Nxf4
White to move. Black has just played …Nxf4. Petrosian found an exchange sacrifice that keeps the attack alive and crashes through to the king. Can you find it?
Tigran Petrosian vs Boris Spassky
Moscow, 1966. Tigran Petrosian, famous as the most impregnable defender who ever lived, was defending his title against Boris Spassky. In Game 10 the 'Iron Tigran' showed the other side of his genius: he absorbed Spassky's pressure, then struck with a flowing attack capped by an exchange sacrifice. It is often called Petrosian's World Championship Immortal, proof that the great defender could attack with anyone.
The lesson
Defence and attack are two halves of the same skill. Petrosian neutralised Spassky's initiative first, then switched to attack the instant the balance tipped — and didn't hesitate to give up the exchange (24.Rxf4!) to keep the assault flowing. Sound defence earns the right to a decisive attack.
Move by move
9. Nd29.Nd2 — Petrosian is content to manoeuvre and let Spassky commit himself; classic Iron Tigran patience.
12… f512…f5 — Spassky seizes space and goes for the attack; the game sharpens.
15. f315.f3! Petrosian challenges the centre and prepares to open lines on his own terms.
18. Qxb218.Qxb2 — the dark-squared bishops are gone and Petrosian's queen eyes the long diagonal toward Black's king.
20. gxf420.gxf4 — Petrosian opens the g-file; suddenly the defender is the one attacking.
22. Rxf122.Rxf1 — material is level but Petrosian's pieces are all aimed at the king. The strike is coming.
24. Rxf424.Rxf4! The exchange sacrifice. Petrosian gives up the rook to keep the attack flowing and open the f-file decisively.
25. Be6+25.Be6+! The bishop check forces the rook to a fatal square and the king into the open.
27. Nxd627.Nxd6 — the knight joins with tempo; Black's defences are stripped away.
29. Bxf7+29.Bxf7+ Rxf7 — clearing the way for the final blow on the eighth rank.
30. Qh8+30.Qh8+ — Spassky resigned. Mate follows. The great defender had played a flawless attacking masterpiece.
Frequently asked
Why is this called Petrosian's Immortal?
Petrosian was famous as the greatest defensive player of all time, so this flowing attacking win — crowned by the exchange sacrifice 24.Rxf4 — surprised everyone and is remembered as the finest attacking game of his career.
Did Petrosian win the match?
Yes. Petrosian defeated Spassky in the 1966 World Championship match to retain his title, becoming the first champion since Alekhine to win a title defence. Spassky took the crown in their 1969 rematch.
Can I try the combination myself?
Yes — take the board as White at move 24 and try to find the exchange sacrifice and the attack, or replay the whole game move by move, no sign-up.