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.

The only thing we need to do is to watch the b1-h7 diagonal. If the king arrives to g6, Black will give a check with the bishop!

Still a draw!

White develops a smart plan to play on the queenside, where he has a space advantage and is fighting against the a5-bishop which is a bit misplaced.

White threatens b4.

Using the pin along the a-file.