Very clever, sometimes frustrating but in that amazing way hat only a great puzzle game can achieve! Thank you for making this amazing little experience.
The chess-puzzle solution is flawed.
I have scanned every possible square, which gave me a solution of
18 3-piece squares, 12 5-piece squares, 7 7-piece squares and 1 9-piece square
yet 18120701 doesn't work... WHY?