07 Oct '20 04:07>1 edit
@greenpawn34 saidAsking "what is that piece doing?" is a helpful technique for solving many types of chess problems. [It can occasionally be less than helpful, if said piece turns out to be a "cook-stopper".]
Hi BigDoggProblem
I never noticed the Black Knight ends up on it's original square.
This makes it all the more amazing.
I got the idea for that one fairly quickly.
It was the placing of the f6 Knight and why was it there.
(it is how I have stumbled upon a few solutions....what is that piece there for.)
[fen]8/1B6/2r2n2/K7/5b2/5k2/5P2/1r1n4 b - - 0 1[/fen]
I ...[text shortened]... e King is in a mating net
waiting for Bxc6. Then it's just a matter of getting the White King to e1
Speaking of Rundlaufs...
U. Heinonen
Proof Game in 22.0 moves
[which means, find a legal game of chess that produces this position right after Black's 22nd move]