No.1788
Gábor Tar
(Hungary)
Original Fairy problems
JF-2023:
01.01.2023 - 31.12.2023
No. 1788 Gábor Tar
Hungary
original - 22.12.2023
black Sc1 Pd3b3f4d5a5b6e7 Kc5 Bh8
white Pd2b2f3a4b5 Kc3 Rf6
ser-hs=10 7+10
Solution: (click to show/hide)
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!
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?
Interesting question, applicable for some later black moves also.
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.
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)
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.
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.
>>> 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.
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).
“It ain’t over until the fat lady sings”. After e2, the fat lady isn’t singing, so it’s not over yet…