White can easily make a draw by playing 1.a7. Therefore a win has to be found. The only way to try is to preserve the a-pawn thus 1.Nb4 is required. As 1…Bh4 2.Nxa2 Bxe1 3.Nc1 wins, Black has to try 1…Ra4 but then 2.Rxe2 Ra1+ 3.Kh2 Bf4+ 4.g3 Bd6 5.Ra2 wins. Therefore 2.Rxe2 Rxb4 3.a7 Ra4 4.Re8+ Kg7 5.a8Q Rxa8 6.Rxa8 should be the mainline. This position should be winning. (With the f-pawn being on h7 instead it would be a well known fortress(6…h5).)
White can easily make a draw by playing 1.a7. Therefore a win has to be found. The only way to try is to preserve the a-pawn thus 1.Nb4 is required. As 1…Bh4 2.Nxa2 Bxe1 3.Nc1 wins, Black has to try 1…Ra4 but then 2.Rxe2 Ra1+ 3.Kh2 Bf4+ 4.g3 Bd6 5.Ra2 wins. Therefore 2.Rxe2 Rxb4 3.a7 Ra4 4.Re8+ Kg7 5.a8Q Rxa8 6.Rxa8 should be the mainline. This position should be winning. (With the f-pawn being on h7 instead it would be a well known fortress(6…h5).)
Nb4 (my ICC handle ;-)) then Bh4 (Ra4 Re2 Rb4 a7 Ra2 Re8+). 2. Nxa2 Bxe1 3. a7 Bg3 4. a8Q Kg7 5… hmmm… is just =. Ah so perhaps 3 . Nd3!
Hnmmm… ooops Didn’t mean Nd3 but 3. Nc1 then 3…. Bf2 4. Ne2 and I’ve won the the e pawn at least …. then nd3/b4/c6
My 2-cents:
1. Nb4 Ra4 2. Rxe2 Rxb4 3.Re8+ Kg7 4.a7 Bf4 5.g4 +-;
1. Nb4 Ra4 2. Rxe2 Bf4 3. Re8+ Kg7 4. g4 and white is a solid pawn up;
1. Nb4 Bh4 2. Nxa2 Bxe1 3.Nc1 +-;
1. Nb4 Rd2 2.a7 Rd1 3.Nc2 Bh4 4.a8Q+ Kh7 5. Qa5 +-.
Cubas – Delgado Ramirez, Uruguay 25/11-2013
White played 41. Nc3?? and after 41…Rxa6 the game was quickly drawn.
The winning line was: 41. Nb4 Ra4 (41… Rd2 42. a7 Rd8 43. Rxe2 Ra8 44. Nc6 Bf4 45. Rb2 $18) 42. Rxe2 $1 Bf4 (42… Rxb4 43. a7 Ra4 44. Re8+ Kg7 45. a8=Q Rxa8 46. Rxa8 with a technically winning ending) 43. g4 Kg7 44. Ra2 and White wins.
So a slight improvement on variation two in Indra Polak’s lines.