g4! Kb2 2 Ra1!! Ka1 3 kc2 a5 4 kc1 a4 5 kc2 a3 6 kc1 h6 7 kc2 h5 8 g5 h4 9 g6 h3 10 g7 h2 11 g8=Q h1=Q 12Qg7 mate. Note that depending on the move order white may need to play the tempo move g3, white needs his king on c2 as on c1 it gets checked when black promotes. I am pretty sure this is the right idea though.
Hmmm… Nagaraj actually was on to something. 1 g4 Kb2 2 Rf6! a5 3 Rf2Kb3 (Kb1 4 Kc3 a1=Q 5 Kb3 and Rf1) 4Rf1 Kb2 5 Ra1!! now Ka1 6 Kc2 h6 7Kc1 and the tempi work for white now for the win. I said I had the right idea, not necessarily the right move order. White needs to tempo with nagaraj’s Rf6 idea or 3…h6 does seem to draw for black.
Every post so far has a little piece of the answer.
1) The solution does in fact start with
1.g4 Kb2
2) The maneuver of Rf6 to force a6-a5 is important;
3) The rook sacrifice on a1 is thematic.
4) Each side has all sorts of persistent tempo issues, some of which are:
a) Should Black play h7-h6 or h7-h5? b) Should White play his king to c1 or c2? c) How many tempi should White force / allow Black to burn with his rear a-pawn?
The trick is that the white king needs to be on C2, not C1 when the h pawn promotes right after his g pawn promotes. Then he can move the queen to g7 with mate.
g4, kb2 ra1, kxr k-c2, h6 g3,
then just need to keep moving the king to C2-C1 until the h pawn is forced to move. When it does, ignore it and promote the g pawn.
g4! Kb2 2 Ra1!! Ka1 3 kc2 a5 4 kc1 a4 5 kc2 a3 6 kc1 h6 7 kc2 h5 8 g5 h4 9 g6 h3 10 g7 h2 11 g8=Q h1=Q 12Qg7 mate. Note that depending on the move order white may need to play the tempo move g3, white needs his king on c2 as on c1 it gets checked when black promotes. I am pretty sure this is the right idea though.
-Justin Daniel
1. Rf6 a8=Q 2. Rb6+ Ka3 3. Rxa6+ Kb2 4. RxQ+ KxQ. Then white king escorts its pawn to the eighth rank.
– Ngaraj
Nagaraj, I did not consider Rf6 but after …a5 I do not see anything for white other than Rf1.
-Justin Daniel
Daniel beat me to it. This was easy for me since I’ve already seen this theme before.
Sammy Slloan says g4, then Ra1 wins ez
Daniel has it WRONG. His play leads to a DRAW with 3….h6 and white is stuck.
So please try something different.
Hmmm… Nagaraj actually was on to something. 1 g4 Kb2 2 Rf6! a5 3 Rf2Kb3 (Kb1 4 Kc3 a1=Q 5 Kb3 and Rf1) 4Rf1 Kb2 5 Ra1!! now Ka1 6 Kc2 h6 7Kc1 and the tempi work for white now for the win. I said I had the right idea, not necessarily the right move order. White needs to tempo with nagaraj’s Rf6 idea or 3…h6 does seem to draw for black.
“1 g4 Kb2 2 Rf6! a5 3 Rf2Kb3 (Kb1 4 Kc3 a1=Q 5 Kb3 and Rf1)”?
5…a4+ wins for Black.
1.g4 Kb2 2.Rf6 a1=Q is a small improvement over 2…a5
Okay, I cheated. Susan, you are a sadist.
Every post so far has a little piece of the answer.
1) The solution does in fact start with
1.g4 Kb2
2) The maneuver of Rf6 to force a6-a5 is important;
3) The rook sacrifice on a1 is thematic.
4) Each side has all sorts of persistent tempo issues, some of which are:
a) Should Black play h7-h6 or h7-h5?
b) Should White play his king to c1 or c2?
c) How many tempi should White force / allow Black to burn with his rear a-pawn?
5) How does White avoid stalemate?
The complete solution is very complicated.
The trick is that the white king needs to be on C2, not C1 when the h pawn promotes right after his g pawn promotes. Then he can move the queen to g7 with mate.
g4, kb2
ra1, kxr
k-c2, h6
g3,
then just need to keep moving the king to C2-C1 until the h pawn is forced to move. When it does, ignore it and promote the g pawn.
Nice puzzle
1.g4 Kb2
2.Ra1? Kxa1
3.Kc2 h6!
4.g3 a5
5.Kc1 a4
6.Kc2 a3
7.g5 hxg5
8.g4 =
or
1.g4 Kb2
2.Ra1? Kxa1
3.Kc2 h6!
4.g3 a5
5.Kc1 a4
6.Kc2 a3
7.Kc1 h5
8.g5 h4
9.g6 h3
10.g7 h2
11.g8=Q h1=Q+ =
The tempo is wrong; Black queens with check, and draws.
In case you were wondering, the solution starts:
1.g4! Kb2
2.Rf2+! Kb3
(2…Kb1? 3.Kc3 a1=Q 4.Kb3+-)
3.Rf6! a5
4.Rf1 Kb2
5.Ra1!