Helpmate in 2 moves. 2 solutions. Cylindrical board (means: a- and h-files are connected, for example a queen on c8 can move c8-b7-a6-h5-g4-f3-e2-d1 - this is a straight line.)
Attention: on a cylindrical board there are FOUR ways to castle - you can castle with each rook in two ways. For example, in the problem's position black can THEORETICALLY castle in the usual way but also like this - King to g8, rook (moving left and jumping over the king) to f8. Why "theoretically"? because in each case the king passes over an attacked square, which is illegal: note the bishop on e1 - it attacks both f8 and d8.