White to move and win!
- a4!! Kxb2, 2. Ra3!! Kxa3, 3. axb5 a4, 4. b6 Kb2, 5. b7 a3, 6. b8=Q+ Ka1, 7. Qe5+ Kb1, 8. Qe4+ Kb2, 9. Qb4+ Ka2, 10. Kg7! and White wins
a4, b5, Rh1...
As a hint, here is a plausible try that demonstrates how white's king is too far away to aid in stopping black from winning the rook for his last pawn:
1.Rh1 Kb2 2.Rh2 Ka3 3.Kg7 b4 4.Kf6 b3 5.ab3 Kb3 6.Ke5 a4 7.Kd4 a3 8.Kd3 a2 9.Rh1 Kb2=
A truly classic puzzle with which I am already deeply familiar. The first move is kind of tough to find, but it is the second move that is truly spectacular.