the occupation of a weak points . It is an important topic for all chess players because it occur frequently in our games.
“weak points or holes in the opponents position must be occupied by piece, not pawns”
So, in position above , white must play 21.Rxh6! because if 21.gxh6? the weak black square on h6 is more or less can’t be occupied by white piece anymore because and more thing, white have block the h file with his own pawn which block his major pieces ( queen or rooks) to pass trough.
White plan to put his knight at f6 which is more active and it will help white attack on h-file.
22…Rf7 23.Nf6+ Kh8 24.Bh3 24.Kd2 Ne8 25.Bh3 Nxf6 26.Bxe6 24…Bc8 25.Kd2 Rg7 26.f4 Rb8 26…Nf7 27.Rh4 27.Rh1 Nac4+ 28.Kd3 Rbb7 28…Nxb2+ 29.Kc2 Nbc4 30.Bxe6 Rbb7 31.Bxc8 Nxc8 32.Ncxd5 29.b3 Na3 30.e4 dxe4+ 31.Ncxe4 Nxe4 32.Kxe4 Nb5 33.Ke5 Rbe7
When your opponent is weak in certain colour of square ( black or white) , usually he will also weak in another clour of square. In this case, Anderssen has a permenant black squares weakness on his kingside so now Miles exploit Anderssen’s white square with 34.Bf1! Nc7 35.Bd3 1–0 Black resign because he can’t stop white to play Bxg6 next and black’s kingside will be destroy.