Once again, we ask ourselves, what does Black want to do?

The knight on g7 is completely dead.

The difference in activity between the minor pieces is evident.

Another good prophylactic move, stopping the trick on b4. White has a decisive advantage.

Simagin's move is, in Jussupow's terms, 'the real prophylactic thinking.' It stops ...a4 and at the same time, White improves his position.

1...a4? 2.Bc4! This is the point! Amazing! 2...Qxc4 3.Bxf6 The bishop protects the rook on h4. 3...Qb5 4.Bxg7 Kxg7 5.hxg6 +-

Botvinnik knew that the resulting endgame was a draw, even without the h-pawn.

The only thing Black needs to take care off is to make sure the Bishop stays on this diagonal to control the important g6 and e6 squares.

Sooner or later, the pawn will end up falling.