Helpmate on a cylindrical board

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.

Originally posted by David113
[fen]r3k3/8/8/4n3/8/1K6/2B5/4B3[/fen]

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 ...[text shortened]... over an attacked square, which is illegal: note the bishop on e1 - it attacks both f8 and d8.

Something's wrong with this one.

1.Nd7 Bb4 2.Rd8 Bg6# (or reverse the order of Black's moves) hardly requires a cylindrical board.

True.

I posted the problem as it is where I saw it. I don't know what the intended position is.