1. g4 g5 2. h5 and White will push f3 and then his king will march along the first rank and then up the c-file, finally getting to b8 with the R and pawn on the 7th. When Black eventually forces the win of the R for the a-pawn, it will be vital to have his R on the 7th to trap Black's K between g6 and h6 with a white pawn on g4 and black pawns on f6 and g5.

This will prevent ...f5 because of a rook check on the 6th rank which will force Black's K to the 7th rank and allow g"f5, supporting Rg6 to remove the last Black pawn. Black can't play ...g6 as long as the White R is on the 6th rank because the pawn will be pinned after R:f6 and Black will just lose two pawns. If Black moves his K to h7 before pushing ....g6 then R:f6 g:h5, g:h5 just wins another pawn and leaves white with two dangerous passed pawns on the K-side.

So 1. h5 and 2 g4 paralyze Black and white has a tedious but uncomplicated win.