Very instructive game, especially the endgame with the invasion of the 7th rank.

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The Karpov of he mid-1980s would surely play the precise 27 Rb7! when Black faces the dismal choice of ceding the c-file by 27..Rb8 28 Rc7 Rc8 29 Rac1 or the passive 27..Rd6, since Uhlman cannot countenance 27..Rc2 28 Rxb6 Rxb2 29 Ra6 Rd2 30 Rxa5 Rxd4 31 Bc6.

Karpov played the casual 27 Rae1 and the game continued 27..h6 28 Rb7?! (better 28 Kf2 when White remains better but has lost some of his advantage) and now Uhlman played the obliging 28..Rd6 instead of the punishing 28..Rc2! The point is that if now 29 Rxb6 Rxb2 30 Ra6 Rd2 31 Rxa5 Rxd4 32 Bc6 Black has 32..Rd2 with counterplay.

The Rd2 move was not possible in the previous line because the Ra1 is so well placed - in the above line, Karpov could have gone 32 Ra8 trading Rooks and pushed the a-pawn.

220: Anatoly Karpov - Wolfgang Uhlmann 1-0 12.0, Madrid Madrid ESP 1973

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Analysis by Stockfish 15 - 3 threads max:

1. +- (1.85): 27.Rb7 Rb8 28.Ra7 Ra8 29.Rxa8 Rxa8 30.Rc1 f6 31.Rc6 Rb8 32.Rd6 Bf7 33.Kf2 Kf8 34.Ke3 Rb7 35.Rc6 Ke7 36.Ba6 Rb8 37.Rc7+ Kf8 38.Bb5 Rd8 39.Kd2 Rd6 40.Kc3 Re6 41.Rc8+ Ke7 42.Rb8 g5

2. ± (1.38): 27.Rae1 h6 28.Rb7 Rb8 29.Ra7 Ra8 30.Rxa8 Rxa8 31.Rc1 f6 32.Rc6 Rb8 33.Rd6 Bf7 34.Kf2 Kf8 35.Kg3 Ke7 36.Rd7+ Kf8 37.Rc7 g5 38.Rd7 Be6 39.Rh7 Rc8 40.Rb7 Rc2 41.Rxb6 Ke7 42.b3 Rd2 White is clearly better

(Gavriel, 07.12.2022)

While modern engines do indicate 27.Rae1 might be less accurate than Rb7 - the move 27.Rae1 prevents Rc2 counterplay and from a human fallible perspective this seems a great way to "non controversially accumulate advantages" which is a lot of what Karpov is about. Like Capablanca, take Steinitz's accumulation of advantage theory and turn it into a practical way of winning.

Stean in "Simple chess" gives 27.Rae1 as more accurate than Rb7 because of not allowing Rc2. Stean clearly didn't use modern engines but the sentiment remains valuable for practical human chess. It does require some involved calculation and Karpov with his Petrosian style is not interested in being a calculating monster.

Karpov understands the fallibilities of being human and it seems to me that 27.Rae1 is a simple and effective move dissuading Rc2 - if Rc2 then Re8 mating. Aka "Simple chess"

Prevention of "prophylaxis" moves might be 2nd or 3rd or more best computer moves, but as humans, it is very useful rather than have to go into a maze of "if-thens" and not have any holes in analysis.

Prevention aka Prophylaxis is a very human way of treating the position - try and destroy the opponent's counterplay even if it is not the most accurate - there is often greater clarity. It is also the "Art of War" - maybe stimulating Nimzovich - "put yourself beyond defeat before going onto the attack"

To quote Karpov:

"Let us say the game may be continued in two ways: one of them is a beautiful tactical blow that gives rise to variations that don't yield to precise calculations; the other is clear positional pressure that leads to an endgame with microscopic chances of victory.... I would choose [the latter] without thinking twice. If the opponent offers keen play I don't object; but in such cases I get less satisfaction, even if I win, than from a game conducted according to all the rules of strategy with its ruthless logic"