Fairy chess composition
 No.1358 Kenneth Solja (Finland) Original Fairy problems JF-2018/II: July – December’2018

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 No.1358 Kenneth Solja Finland original – 23.12.2018 Merry Xmas and Happy New Year 2019 to every chess composer Solution: (click to show/hide) white Kh1 Ph2 black Ka8b8e7f6f5g4h3 Pg5 h#7                                              (2+8) Royal Dynasty 1.Kg4-g3{display-departure-file} h2*g3 2.Kf5-f4 g3*f4 3.Kf6-e5 f4*e5 4.Ke7-d6 e5*d6 { } 5.Kb8-c7 d6*c7 6.Ka8-b8 c7*b8=Q 7.g5-g4 Qb8-h2 # { (Partly tested, C+ for 6.5 moves by Popeye (Author))} If in the initial position black starts with 1 Khg3, white can try following solution: 1 Khg3? h3 2 Ke6 hxg4 3 Kd7 gxf5 4 Kc8 fxe6 5 Kb8 exd7 6 Kh3 dxc8D 7 g4 Dxb8 which leaves solution half move short. It doesn’t have success because Kh3 moves twice and white needs to capture six kings as economically as possible. As can be seen from the diagram the most economical way of capturing these kings is to move them to diagonal h2-b8. Because of all this we should move first king to g3, but it is not Kh3 instead we move Kg4 to g3. Following solution has been checked with computer from B1 to the end. 1 Kgg3 hxg3 2 Kf4 gxf4 3 Ke5 fxe5 4 Kd6 exd6 5 Kc7 dxc7 6 Kb8 cxb8D 7 g4 Dh2# Black is in a hurry after every white move because there is no room for free move and the cherry in the cake is the return to starting square to mate. This can be shown only with Royal Dynasty fairy condition like this. White minimal. Only Kings and Pawns. (Author)

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François Labelle
December 24, 2018 02:09

Human-computer checked (HC+) with the following Jacobi input:

pieces white Kh1 Ph2 black Ka8b8e7f6f5g4h3 Pg5
stip h~3
test not dia forsyth 64 Add black K K K K K K AddPieces
stip h~2
test not dia forsyth 64 Add black K K K K AddPieces
stip h#2
cond RoyalDynasty

Explanation: After 7 moves, there must be exactly 1 black king, so after n moves there must be at most 8-n black kings. Equivalently, after n moves there must *not* be 9-n black kings or more. This is what the “test” lines are enforcing for n=3 and n=5. I could have enforced it for more values of n, but these two are sufficient for a quick (sub-1-min) verification.

Joost
December 24, 2018 12:50

First move should be Kgg3, not Kg3.

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