Mate in 24?

[Jouni]

[d]8/6Pp/7p/7k/5Pp1/P5P1/1pK5/qB6 w - - 0 1
Huntsman territory:

1.g8B Kg6 2.Bga2 Qxa2 3.Bxa2 h5 4.Kd2 h4 5.Bb1+ Kh5 6.Ke1 hxg3 7.Kf1 Kh4 8.a4 h5 9.a5 Kh3 10.Kg1 g2 11.a6 Kg3 12.a7 Kxf4 13.a8Q Ke5 14.Qe8+ Kd5 15.Qxh5+ Kc6 16.Kxg2 Kd6 17.Qb5 g3 18.Qb6+ Kd5 19.Qc7 Kd4 20.Kxg3 Kd5 21.Kg4 Kd4 22.Kf4 Kd5 23.Ba2+ Kd4 24.Qc4#

[peter]

[d]8/6Pp/7p/7k/5Pp1/P5P1/1pK5/qB6 w - - 0 1
Huntsman territory:

1.g8B Kg6 2.Bga2 Qxa2 3.Bxa2 h5 4.Kd2 h4 5.Bb1+ Kh5 6.Ke1 hxg3 7.Kf1 Kh4 8.a4 h5 9.a5 Kh3 10.Kg1 g2 11.a6 Kg3 12.a7 Kxf4 13.a8Q Ke5 14.Qe8+ Kd5 15.Qxh5+ Kc6 16.Kxg2 Kd6 17.Qb5 g3 18.Qb6+ Kd5 19.Qc7 Kd4 20.Kxg3 Kd5 21.Kg4 Kd4 22.Kf4 Kd5 23.Ba2+ Kd4 24.Qc4#

With at least one move added to (probably) shortest DTM from the position you give, which cuts off the first one move from the original Korolkov- study.

8/6Pp/7p/7k/5Pp1/P5P1/1pK5/qB6 w - - 0 1

Analysis by The Huntsman 1:

1.g8L Kg6 2.Lga2 Kf6 3.Kd2 Ke7 4.a4 h5 5.Ke2 Kd7 6.f5 Kd6 7.a5 h4 8.gxh4 g3 9.a6 Kc6 10.f6 Kb6 11.f7 Kxa6 12.f8D Dxa2 13.Lxa2 Kb5 14.Dd6 g2 15.Kf2 g1D+ 16.Kxg1 h6 17.Lb1 h5 18.Ld3+ Ka4 19.Db6 b1D+ 20.Dxb1 Ka3 21.Lc4 Ka4 22.Db5+ Ka3 23.Db3#
Tiefe: 67/46 00:01:23 5116MN

Deviation from your line is 2...Kf6, after 2...Qxa2 there :
[d]8/7p/6kp/8/5Pp1/P5P1/qpK5/1B6 w - - 0 1 Analysis by The Huntsman 1:

3.Lxa2 h5 4.a4 h4 5.gxh4 g3 6.Ld5 b1D+ 7.Kxb1 g2 8.Lxg2 Kh5 9.a5 Kxh4 10.a6 Kg4 11.a7 Kxf4 12.a8D Ke5 13.Kb2 Kd6 14.Kc3 Kc7 15.Kd4 Kd6 16.Df8+ Kc7 17.De7+ Kb6 18.Kc4 h6 19.Db7+ Ka5 20.Db5#
Tiefe: 72/36 00:02:04 9088MN

4.a4 spares (at least) four moves from your line after Kd2.

Here's the original study like it's given in HHdb:

[pgn][Event "Vecherni Leningrad"] [Site "?"] [Date "1947.??.??"] [Round "?"] [White "Korolkov=V"] [Black "(+0010.45d1h5)"] [Result "1-0"] [SetUp "1"] [FEN "8/6Pp/7p/7k/5Pp1/P5P1/pp6/1B1K4 w - - 0 1"] [PlyCount "5"] [EventDate "1947.??.??"] 1. Kc2 (1. Bxa2 $2 b1=Q+ 2. Bxb1) 1... a1=Q 2. g8=B $1 (2. g8=Q $2 Qxb1+ 3. Kxb1) 2... Kg6 3. Bga2 1-0 [/pgn]

[Jouni]

Thanks. Huntsman is fast in original position as well

Analysis by The Huntsman 1:

1. +- (#24): 1.Kc2 a1Q 2.g8B Kg6 3.Bga2 h5 4.Kd2+ Kf6 5.a4 h4 6.gxh4 g3 7.Ke3 g2 8.Kf2 g1Q+ 9.Kxg1 Ke7 10.f5 Kd6 11.a5 Kd7 12.f6 Qxa2 13.Bxa2 b1Q+ 14.Bxb1 Ke6 15.a6 Kxf6 16.a7 Ke7 17.a8Q Kd6 18.Qa6+ Kc5 19.Kf2 h6 20.Ke3 h5 21.Ba2 Kb4 22.Qb6+ Ka4 23.Bc4 Ka3 24.Qb3#

About 1 minutes.