bronkenstein: Interesting strategical moment happened after white played 23. h4 . I was wondering , why didn´t Botvinnik simply grab the d6 pawn ?
I started checking tactics in the position , lines like 23. ... K:d6 24. <Bf4+> e5 25. <0-0-0+> Kc6 26.<R:g2 ?> R:g2 27. Bg3 <Rg8> and black is prolly winning ... Then i tried lines like 23... K:d6 24. <0-0-0+> Kc6 25. h5!? <Rg4> 26. d6 ? <Bf3> , and white has nothing .
Tactics! Bleh ! Typical me ... The strategical key to this position is different colored bishops endgame that is soon to come . Check the position after , lessay , move 40 . White has ´decorative´ totally blocked and harmless central pawns (remember d6 ? ;), while black created dangerous passed pawns on A and F lines , being the only one with chances to win .
I recommend Kotov vs Botvinnik, 1955 , as very instructive example of how important far separated passers are in different coloured bishops endings , check it from 59. ...g5 ! untill the end . Absolute Classic :)