Fundamentals (part 33)

Spanton (2032) - Adam Ashton (2294)
Isle Of Man 2005

White to play and draw

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53.Ka2!
White loses after 53.axb6 Kxb6, eg 54.Kc2 Ka5 55.Kc3 a6 (this reserve tempo is crucial) 56.b4+! (the best shot as 56.Kc2 loses to 56...Kb4 57.Kb2 a5 58.Kc2 a4 59.bxa4 Kxa4 60.Kc3 Ka3 etc) Kb6! (not 56...cxb4+ 57.Kb3 Kb6 58.Kxb4 when Black needs to find 58...Kb7! to draw) 57.Kb3 Kc6! 58.Kc3 cxb4+ 59.Kxb4 Kb6 etc.
Also losing is 53.Ka3 although not because of Stockfish10 and Komodo10's top choice 53...b5, which only draws, eg 54.Kb2 b4 55.Ka2 Kb7 56.Kb2 Ka6 57.Ka2 Kxa5 when the engines somehow reckon Black is winning even though Black cannot make progress. However Black can play 53...Kb7!, which wins because White will eventually be forced to capture on b6, losing as in the first line of this note.
53...bxa5
If 53...Kb7 then 54.Ka3 when 54...Ka6 can be met by 55.Ka4.
If 53...b5 then 54.Ka3 when 54...b4+ (54...bxc4 55.bxc4 Kb7 56.Kb3) 55.Ka4 a6 is stalemate.
54.Ka3 Kb6
If 54...a4 then 55.bxa4 draws but 55.Kxa4? loses to 55...Kb6 etc.
55.Ka4 Ka6 56.Ka3 Kb6 56.Ka4 Ka6 ½–½