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MatPlus.Net Forum Promenade The dance (a short puzzle story)

(1) Posted by Siegfried Hornecker [Thursday, Feb 18, 2021 08:20]

### The dance (a short puzzle story)

The battle was over. All the opposing pieces were captured. White had a fantastic idea. While he was watching from afar, Black would have to do a dance show. On the squares where usually his own pieces stood, the opposing pieces would appear, one by one. The only issue was that they should not be able to communicate. The king could be restricted easily, being not fast in the first place, from reaching the first rank. But if any piece would run away and get to the king in a matter of seconds - a single move, as the ancient timetable said - the Black forces could possibly do something bad. This had to be prevented.

So a few rules were established for the first show:
The black king would start on the a-file and march to the d-file.
During that time, on the first rank one officer would appear on its starting square (if it would have been white), but in a way as to not be able to reach its king in a single move.

Starting squares - a-d for the first, a-h for the second show with d1 double appearance.
(= 0+8 )

The king started his dance on a3, then moved to b2, c3, d2 - so the pieces that danced with him appeared in a specific order that can be determined from his dance pattern.

a) What was the order the pieces appeared in?

A second show was held, but this time the king would start on a3 again and move to the h-file, with the entire army appearing (except the pawns who long ago returned to being farmers again) - the queen even twice. That plan seemed perfect until, shortly before the show, a small issue was pointed out. One of the squares in the upper half of the board was made inaccessible for the king to make sure the pieces could appear as they should - each officer's rank twice: queen d1, rook a1/h1, knight b1/g1, bishop c1/f1, without being able to communicate with the king.

b) What square was made inaccessible?

Note: Please use in hard brackets w and /w for the solution, to avoid spoilers for others. I hope you understand what I try to tell (i.e. what the puzzle is about). A piece essentially is added so that it doesn't "see" the king, then removed before the king moves, and so on.