[Retros] Self-protecting Chess puzzles

[Eric Angelini]

Hello Retro-fans,
[this is my third msg to the list with the same concern;
 I re-subscribed a few seconds ago because the two first
 didn't show in my mail-box (nor in the archives). If this
 is old hat, please forgive me. Here is my former 8/I msg.
 Since then I've added a 64 US$ reward, somewhere on the
 page]

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Hello Retro friends,
Start the year with this light idea:
http://www.cetteadressecomportecinquantesignes.com/SPCdiag01.htm
Best,
É.

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Self-protecting Chess diagrams are legal chess positions with 8 white pawns, 8 white men and no black piece at all (but one empty square, at least, must be available for the Black King).

The SPC concept claims that every piece protects exactly one other piece and is protected by exactly one.

This can be achieved by one giant loop (like in diag.1), where  A protects only B, which protects only C, which protects only D, etc. until P which protects only A (start with the Queen in a1 and check):

(...)