The position is a bit complicated, so it's possible I've overlooked something.  I believe Mate in 6 is the best White can do.

i'm pretty sure you're right.  good puzzle.

with a queen extra you'd hope it would never be more than mate in 6 :)

ya pretty good puzzle

Certainly true, just thought the first move was interesting.  Most people with that much bonus wood try to pound down the doors, not seal them up.

yes - that was clever. did the computer agree with that move?

Can be done in 5

This is what Herr Fritz says, the recommendation is 1. Ne4 with mate in 6 still the end result, I can't see any easy way for mate in 5 unless black blunders or skips a spite check.

 can u explain how? there r several ways to do it in 6 (depends on black moves) but i havn't seen a way to do it in 5

hmm.  i don't see how five, i see a few different ways in six.  ie

1.Ne4 Re1+

2. KxR g5

3 NxB+ Kg6

4. Nh4 (now black has a choice we will call it a: and b:)

4a.... Kh7

5.Qf5+ g6

6.Qf7#

4b.... Kf7

5.Qe7+ Kg6

6.Qxg7#

Hm... a little disappointed that there are different solutions.  I enjoyed the final mate with the Knight in the Ne4 variation, but I don't see yet what the Bxb2 move accomplishes.  I know it was computer analysis, and it's probably a scenario where there is nothing functional to be done, so it takes a piece because it has nothing else to do.  I was just hoping the g5 solution was the only one, because every move there serves a precise function.

Twas a fun discussion nonetheless.

Edit: fixed an incorrectly stated move (there is nothing for the Bishop to take on a2, dummy).

The 'g5' solution does not have every move serving a purpose (unless that purpose was to delay your own mate). When Black responds correctly: 1 ... Bxc3, it doesn't only take a piece 'because it has nothing else to do.' It also delays mate because if you ignore the bishop with 2. Qf8?! then 2 ... Re1+!? and Black creates an absolute skewer to win your rook, removing forced mate.

What else could the purpose of ANY move be when you're guaranteed to be mated shortly?

As with any chess puzzle, Black should've resigned already if he saw his fate.  The interesting part of mating puzzles is to find the (ideally unique, hence my dismay) solution to the fastest mate, assuming best play (which can only be defined as delaying mate as long as possible) by the defender.

My Bxa2 comment (by which I meant Bxb2, sorry) was in regards to the Ne4 line.  I agree that 1. g5 Bxc3 Qf8 fails, but I do not agree that it is more 'correct' for Black than Bxg5; both lead to Black's death in the same number of moves (as demonstrated by Eniamar).

nice