White to play and mate in four.

Hint:White's main plan is to transfer his knight to c7.After 1 Nd8, for example, he threatens 2 Ne6 and 3 Nc7. At this stage it isn't obvious why 1 Nb4 and 1 Ne7 might be different, but of course it will turn out that only one of these three moves works. Black defends by 1...***, but White has a surprising reply 2 ***!, which appears to give white the time he needs to complete his knight maneuver. But then Black produces truly imaginative defense 2...***!, which forces white to abandon his plan of playing the knight to c7. Now it suddenly becomes clear why White's first move is unique, because he needs to have the option of 3 *** with mate next move. Now just fill in the blanks.

Very nice

Nothing is forced

Please elaborate?

After 4 hours nothing... So, I guess you changed your mind?

The c pawn to promotion is what prevents white from getting mate with the knight.

Oh that is absolutely fantastic!!! The hints give you a fighting chance, too... I got to Qc1, but Black's defense *(I don't want to give it away) eluded me. And the final mate too... Such a great puzzle. I'm committing this one to memory. Oh, one small point... you mention White needing to choose between Ne7 and Nb4... but there's another N manuver, Nd8;e6;c7 ... so the choice is threeway.

where'd you find that -- who composed that puzzle... that's a prizewinner, it has to be.

I wish people would make a habit of creiditing the composers. I always try to do that, but sometimes I forget too.....

Well...it was composed by Kraemer.

Thanx

but if black promoted to queen instead of a bishop wouldn't that prevent the mate?

If he promotes to a queen, there is no way to prevent Nd-d5-c7#

The idea of the bishop promotion is to give Black a stalemate defense.