Julia's Fairies

No.1788 (GT)

Gábor Tar

Original Fairy problems
01.01.2023 - 31.12.2023

No. 1788 Gábor Tar
original - 22.12.2023

black Sc1 Pd3b3f4d5a5b6e7 Kc5 Bh8 white Pd2b2f3a4b5 Kc3 Rf6
ser-hs=10                       7+10

Solution: (click to show/hide)

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December 23, 2023 01:33

White is already in stalemate! But the stipulation requires white to force black to play a stalemate move. So the white rook has to be unpinned! Interesting idea!

Last edited 2 months ago by Seetharaman
Georgy Evseev
Georgy Evseev
December 23, 2023 16:11
Reply to  Seetharaman

This is the matter for discussion.
Is 4.e2 legal?
Black stalemate white, while they are not forced to do it. Can the solution continue after that?

December 24, 2023 12:19
Reply to  Georgy Evseev

Interesting question, applicable for some later black moves also.

Dmitri Turevski
Dmitri Turevski
December 24, 2023 13:31
Reply to  Georgy Evseev

I think it is legal.
According to most definitions, the aim of (ser-)hs= is not a stalemate position, but a s=1 position, therefore after 4.e2 the aim is not yet reached and the solution doesn’t terminate.

Georgy Evseev
Georgy Evseev
December 25, 2023 08:43

As I had written, this is a matter for discussion. There is no definitive rule, so this is a (unfortunately) standard for fairy chess “condition branching”.
For example, the following scheme may be also considered valid:
b7/8/3p4/8/p5p1/6pk/P5Rp/7K – w ser-hs=2
1.a3? 2.d5 Rxh2+ gh= (wrong as white are stalemated after the first move)
1.d5! 2.a3 Rxh2+ gh= (correct)

shankar ram
shankar ram
December 25, 2023 15:37
Reply to  Georgy Evseev

In line with Dmitri’s explanation, which I agree with, both the solutions: 1.a3 2.d5 and 1.d5 2.a3 would be correct. Help-self problems can be defined as having a “nested goal”, in this case, a s=1. The goal is to reach a position where White can s=1. If Black himself stalemates White, the goal is not achieved. See also SuperProblem 2019 G223 for a more complicated example.

Dmitri Turevski
Dmitri Turevski
December 25, 2023 15:52
Reply to  Georgy Evseev

One may argue that 1.a3? is not a stalemate at all under the series-help rule, where white can (and must) play pass/null moves.

Last edited 2 months ago by Dmitri Turevski
Georgy Evseev
Georgy Evseev
December 26, 2023 08:53

>>> white can (and must) play pass/null moves.
This is exactly my point. Why in series-mover black cannot make illegal moves (like Kb4 with wPa3), while both the position before and after the move is BTM-legal? Because we make a WTM-check before continuing, don’t we?
So, here during WTM-check we will find a stalemate position and may declare a GameOver.
Anyway, I understand the author’s intention (it was obvious), but do not like the separation of stalemates into “good” and “bad” ones. There is no such separation for checkmates.

Dmitri Turevski
Dmitri Turevski
December 26, 2023 14:10
Reply to  Georgy Evseev

It looks like all these complications could be avoided if series play was defined as a fairy condition that modifies the set of legal moves, just like maximummer, for example, with both sides playing strictly in turn. 
1.a3 pass (here pass-move is legal and is the only legal white move) 2.d5 Rxh2+ 3.gxh2=, 3…pass? (here pass-move is illegal because the series phase has ended with 2…Rxh2).
And Kb4 with wPa3 would be illegal simply because of the FIDE rule 3.9 (cannot make move that leaves or places your king in check).

Joost de Heer
Joost de Heer
December 27, 2023 11:35

“It ain’t over until the fat lady sings”. After e2, the fat lady isn’t singing, so it’s not over yet…

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