Maryan Kerhuel & Jacques Rotenberg
(France / Israel)

Warm welcome to Maryan!

Original Fairy problems
01.01.2021 - 30.06.2021

Definitions / Определения

No. 1618 Maryan Kerhuel &
Jacques Rotenberg

France / Israel
original - 31.05.2021

white Kd3 Rf3 Black Ka1 Pf2
hs#4            b) Kd3-->g2, c) Kd3-->h2,
d) Ka1-->c1            2+2

Solution: (click to show/hide)

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Joost de Heer
Joost de Heer
June 1, 2021 12:45

Question: When is ‘are no pieces around’ evaluated? Before the move, during the move, or after the move? Legality of e.g. castling or a move resulting in a rebirth depend on the moment of evaluation. E.g. with wRa1, wKe1, wPf2, is castling allowed? (c1 has no neighbours before the move, but has after the move) Or wPc6, bRb7 Circe. Is c6xb7 allowed?

Jacques Rotenberg
Jacques Rotenberg
June 1, 2021 16:59
Reply to  Joost de Heer

Joost, I just quote here comments that have been published here in a general place

shankar ram
June 1, 2021 02:24
Antineuköko :
Any unit standing adjacent to an occupied square may not move to finish adjacent to an occupied square, and any unit not standing adjacent to an occupied square may only move to finish adjacent to an occupied square. An attacked King will only be in check if its capture would be allowed under those conditions.
 June 1, 2021 11:40

Jacques Rotenberg
June 1, 2021 11:40
Also possible :
Antineuköko :
Let’s call a “mirror piece” a piece standing on a square with all the adjacent squares (max. 8) empty.  
a mirror piece must be non-mirror after its move and a non-mirror piece must be mirror after its move. Other moves are illegal.

some people may think “adjacent” is just for the 4 squares on the sides, so to be clear I added (max.8)

so, to answer your questions, following these definitions
1- 0-0 or 0-0-0 are ok if both the moving rook and the king are on “free” squares (or “mirror” squares before this move
2- the move c6xRb7(Ra8) is illegal
3- a check (or a capture of a king) is valid only if the move is legal

Jacques Rotenberg
Jacques Rotenberg
June 6, 2021 21:20

I feel that some explanations may be useful :

1.Ke3 f1=S+ 2.Kd2 Sg3 3.Ra3 Se2 4.Kc1 Kb2‡
3.Ra3 allows the black king to go to b2 where he will not be checked by the white king. 3.Rb3? seems equivalent but allows 4.Ka2! This promotion in knight is the most unexpected of the four
1.Kh1 f1=B 2.Rf2 Bh3 3.Rh2 Bf1 4.Rh3 Bg2‡
4.Rh8? Bg2+ 5.Rh2!
1.Kg3 f1=Q 2.Kh2 Qh1+ 3.Rh3 Qc6! 4.Kh1 Qg2‡
3.Qa8?/Qb7?/Qd5? would allow the queen to go to a2, b2, b1
1.Ke4 f1=R 2.Kd5 Rf2 3.Rb3 Kc2 4.Rb8 Rd2‡
4.Rb7? Rd2+ 5.Kc6
2.Ke5? Rf2 3.Rc3 Kd2 4.Rc8 Ke1(e2,e3)!