Wait, the instructions are a little ambiguous. I clicked "Solution" and it has the dark-squared bishop on a white square! XD
Should maybe update the instructions to clarify that the dark-squared bishop is not constrained to dark squares.
The instructions likely mean that the bishop itself is black, not the square that it is on.
that's exactly what happened to me. I ended up spending so much time thinking black bishop can only go to black squares. and agreed this is a bit ambiguous.
> The task is to place four black queens and one black bishop on the chessboard
where did you read "dark-squared"?
It's a black bishop, but not necessarily a dark-squared bishop. Both the black side and white side in a normal chess game get a dark-squared and a light-squared bishop, and I don't see anywhere that specifies which type this one is. It can be either one depending on where you place it.