Forced mate

After Black's second move, everything is forced. It also looks like a legal chess position.

Actually, every branch leads to forced mate.

Mate in 10 (legal position!)

Maybe you can show how this position arose.

Very nice position. The previous Black move must have been Rd5-e5+.

Actually is not one of mine.

There are "simple" positions known where one has to deliver mate if he wants or not. And once again, if the mating side oversteps the time it is a draw if the other side has no legal way to a win.