Very good puzzle! Thank for teach me! Never see like this before. Have you got any puzzle like this?

yes

In Jesper Hall's awkwardly titled, but excellent book, "Chess Training for Budding Champions", the author gives the above puzzle...and then after his friends (victims?) solve it, he ROTATES the board 180 degrees, apologizing, noting that it is still mate in three...

Nice instance of zugzwang.

Also, nice addition, nimzovich.

my math teacher once showed me both of them :)

Watch out for those math teachers.

Almost as sneaky as chess players...

I wish one of my math teachers was as sneaky as a chess player. Then maybe my school would have a sponsor for the chess club again. Even though I routinely lost my games last year, I think I can hold my own against them now, and I want to play on third board (or maybe even second if I improve enough) come the team championships.

Here is mate in 3

Isn't that a simple #2 metzer?