Retractor understanding of unblocking files #16
Description
https://www.janko.at/Retros/d.php?ff=N3R2n/p2p1p1N/1p1k1Pp1/QKpPp3/2p5/qB6/rB1R4/bn6
#2 (after Paul Vatarescu)
To get this right, retractor must get a couple of things:
(1) Black pawn captures are mostly obvious: h7xg6, g7xf6xe5, exdxc (and retractor does get this!)
(2) wPh must capture to get involved (bPh only unblocks h-file after bNh8 blocks it again) (I don't think retractor gets this.)
The sole ok retraction should be c7-c5.
This is a simple but tricky problem, and I thought it would be good for Retractor to digest.
It's also the first time, afaik, that an original chess problem has been published in Github!