ToTheDeath: This is a model game on how to play against an isolated Queen pawn, and how to play for a win with Black.
<10...Nf6> Prophylactic play preventing 11.Qe4 followed by Qh4 and Bg5 with kingside initiative.
<12...Qb6!> Getting the queen off the back rank and preparing to connect the rooks. Of course Karpov doesn't play 12... Nxd4? 13. Nxd4 Qxd4 14.Bc3 with a big initiative for White.
<13...Bd7> Taking on b2 would lose the queen to 14.Rfb1.
<14...Rfd8> Karpov decides to put his queen's rook on d8, keeping his other rook on f8 in case of Ne5 and Ng5 with threats to f7.
<17...Ne7!!> Again 17...Qxb2? 18.Rfb1 Qc3 19.Bd2 would lose the queen. Karpov sidesteps the threat of 18.d5 and prepares Nf5. If now 18.d5 Qxb2! is a safe capture- Black win two rooks for the Queen.
<19...Qa6!> 19...Qc7 20.Bf4 and 19...Qc6 20.Na5 were considerably weaker. Karpov is unafraid of 20.Ne5 Bb5! with Black in charge of the light squares.
<21...Bd5> Now the problem piece for Black in so many queen's pawn games has achieved an ideal post for attack and defence.>
<22...Qb6> Black is prepared for 23.g4 g5! winning the queen.
<30...Re4!> White has to meet the threat of ...Rg4.
<31...b5!> preventing any activity for White's a1 rook.
<33...h6> a simple patient move making luft in the event of a back rank check.
<35...Rc6> Provoking 36.d5 Rc8 37. Rdc1 b3 38.Rd2 Be5, where White is under heavy pressure.
<38...Bxc6> here again 39.d5 Ba8 40. b3 Be5 is in Black's favour.
<39...Bf8!> Preventing any counterplay with Rb4.
<40...Qe6> A time pressure move, 40...Qd5 41.Ne5 Rxe5 42.Rxc6 Rxe3 wins faster. Black had to avoid 40...Rg4? 41.Ne5! Rxg3 42. Nxd7 Rxg2+ 43.Kh1! when Black has too much hanging.
<43...Bd6!> Not 43...Qa6? 44.Bc5 defending. Now if 44.f4 Qd7! 45.Bd4 (45.Be3 Bxd3 46.Qxd3 Bxf4+ wins) Bxd3 46.Qxd3 Bxf4+ 47. g3 Be5 winning.
<44...Qe5> Now 45.Be3 Qxb2 46.a6 Qc3 and only Black's pawn is promoting.
<45...Qe7> The concluding stroke- the bishop on a7 is lost.
Terrific game by Karpov.