White to move and mate in 4. No queening!

 

EDIT: this has been proven as inefficient/unsound.

 

Feel free to 'solve' it anyway 

Quote: White to move and mate in 4. No queening!

What's the point? The rook underpromotion served no purpose with no threat of stalemate, only the final underpromotion made sense. Mate in 2 with queening allowed. 

you cant mate in two. admittedly a8=Q+ Kc7 Qc6+ Kb8 Qb7# is 3 moves, but i dont see a way to do it in 2.

 

Maybe it needs refining. I was considering posting the following, but it seemed a little simple. I overcomplicated it in a hurry

Can't be done in 2

 

The second puzzle can be solved without underpromotion by 1. b8=Q+ Kd7 2. Qd6#

@ Evil_Homer, your wrong.

 

In the second diagram, the newly promoted queen can also mate at e8.

 

 

Yes, the 2nd diagram you can, but your post #3 refers to the 1st puzzle.

This is the mate in 2 solution to the first problem, if queening is allowed.

Hey thanks I didn't see that.

I was intrigued by a knight promotion to mate (I brought it up in another thread in general discussion) and made this puzzle in about 30 seconds. I may spend some time making a sound puzzle next time! - the aim is a simple puzzle which finishes =N#

  

Thank you for the lesson, much apprciated :-)

I like puzzles that end in a knight promotion too, but I prefer it if they are a bit more complicated and the knight promotion is necessary to win in the fewest moves. I also  prefer puzzles that look like they are taken from somewhere in the middlegame or endgame than composed unlikely positions, but thats just me.