The story behind the game
Tigran Petrosian’s tenth game against Boris Spassky in the 1966 world championship illustrates why a rook’s nominal value does not tell the whole story. Piece activity and weak squares shape the position, and the later tactics grow from that imbalance.
Take these ideas to your next game
- Judge an exchange sacrifice by squares and activity as well as pawns.
- An unopposed bishop can become more useful than a passive rook.
- Do not allow a material advantage to hide a weak king.
- Look for tactical consequences of a long-term positional advantage.
Read the complete annotated game
Full game transcript, including the result and the answers. Original explanations by chessgames.info; game score from the sources below.
A pawn exchange can change the value of every nearby piece. Petrosian’s 20.gxf4 changes the kingside structure. Black answers …Bh3 and soon captures the rook on f1, but White’s minor pieces gain activity in return. Evaluate the resulting squares and king safety as well as the nominal material. The saved alternatives help distinguish compensation from an unsupported general rule about exchange sacrifices.
Do not protect a rook at the cost of making the whole army passive. The historical 21.Ne3 develops the knight toward useful central squares while Black captures on f1. White recaptures with the other rook. Study the resulting position rather than treating the exchange as a standalone trick: White’s bishops, knight and exposed targets give the material imbalance its meaning.
Positional pressure becomes tactical when the pieces are ready. Petrosian plays 24.Rxf4, and Black’s rook recaptures. White follows with Be6+, bringing the bishop into an attack with tempo. The combination illustrates why a rook’s value depends on what it can do and which squares the minor pieces control. Follow the forcing sequence before deciding whether the extra exchange is useful to the defender.
A quiet king move can preserve a forcing finish. After …Qg5+, White plays 28.Kh1. The game soon concludes with Bxf7+, …Rxf7 and Qh8+. This is a useful reminder to calculate defensive steps inside your own attack. A move that simply gets out of check can be the bridge to the final sequence, provided the pieces remain coordinated.
Result: 1-0. The recorded score ends here; it does not imply checkmate.
Think through the turning points
Move 20: Decide which files matter
How should White meet the pawn contact on f4? In the game: gxf4. A pawn exchange can change the value of every nearby piece. Petrosian’s 20.gxf4 changes the kingside structure. Black answers …Bh3 and soon captures the rook on f1, but White’s minor pieces gain activity in return. Evaluate the resulting squares and king safety as well as the nominal material. The saved alternatives help distinguish compensation from an unsupported general rule about exchange sacrifices.
Engine-supported alternatives
Rxf4 Rxf4 gxf4 Ng6 Nf2 Nxf4 Nde4 Nxe2+ Qxe2 Ra7 Kh1 Rg7 · +1.67 · depth 19
gxf4 Rxf4 Rxf4 Qg5+ Kh1 Qxf4 Nc3 Ra7 Rg1+ Rg7 Rxg7+ Kxg7 · +0.35 · depth 19
Kh1 f3 · +0.18 · depth 19
Move 21: Keep the pieces active
How can White improve coordination while allowing the material imbalance? In the game: Ne3. Do not protect a rook at the cost of making the whole army passive. The historical 21.Ne3 develops the knight toward useful central squares while Black captures on f1. White recaptures with the other rook. Study the resulting position rather than treating the exchange as a standalone trick: White’s bishops, knight and exposed targets give the material imbalance its meaning.
Engine-supported alternatives
Ne3 Rxf4 Rxf4 Qg5+ Rg4 Bxg4 Nxg4 Nxg4 Bxg4 Qxg4+ Kh1 Qd4 · +0.56 · depth 19
Ne4 Bxf1 · -0.42 · depth 19
Rf2 Rxf4 Qc3 Qg5+ Qg3 Qxg3+ hxg3 Rd4 Bh5 bxc4 Nf3 Nxf3+ · -0.70 · depth 18
Move 24: Make the imbalance dynamic
Can White use the remaining rook to open a decisive line? In the game: Rxf4. Positional pressure becomes tactical when the pieces are ready. Petrosian plays 24.Rxf4, and Black’s rook recaptures. White follows with Be6+, bringing the bishop into an attack with tempo. The combination illustrates why a rook’s value depends on what it can do and which squares the minor pieces control. Follow the forcing sequence before deciding whether the extra exchange is useful to the defender.
Engine-supported alternatives
Ne4 · +3.44 · depth 20
Rxf4 Rxf4 Be6+ Rf7 Ne4 Qh4 Nxd6 Ra7 Nef5 Qg4+ Kf2 Qf4+ · +3.03 · depth 20
Kh1 Qf6 Qxf6 Rxf6 Ne4 Rff8 Nxd6 Kh8 Nef5 Nd3 Bh5 bxc4 · -0.11 · depth 20
Move 28: Answer the check, keep the threat
How should White meet the check without losing the attack’s coordination? In the game: Kh1. A quiet king move can preserve a forcing finish. After …Qg5+, White plays 28.Kh1. The game soon concludes with Bxf7+, …Rxf7 and Qh8+. This is a useful reminder to calculate defensive steps inside your own attack. A move that simply gets out of check can be the bridge to the final sequence, provided the pieces remain coordinated.
Engine-supported alternatives
Kh1 Qg7 Qf2 Qa1+ Nf1 Rf8 Nxf7 bxc4 Nd6+ Kg7 Qg1+ Kh8 · +4.53 · depth 20
Ng4 Qg7 Bxf7+ Kf8 Qxg7+ Kxg7 Be6 bxc4 Nxc4 Nxc4 bxc4 Kf8 · +3.61 · depth 19
Ng2 Qg7 Bxf7+ Kf8 Qxg7+ Kxg7 Be6 bxc4 bxc4 Kf6 Ne3 Ke5 · +3.11 · depth 19
Every piece has a part to play.
Tigran Petrosian’s tenth game against Boris Spassky in the 1966 world championship illustrates why a rook’s nominal value does not tell the whole story. Piece activity and weak squares shape the position, and the later tactics grow from that imbalance.
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Accessible evaluation values & provenance
Stockfish 17.1 · 75,000 nodes per position; 1,000,000 at key moments. Actual depth 13–20. Positive centipawns favour White; mate scores remain separate. Selective search is evidence, not proof.
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