helpmate

1. e2-e4 ...
White checkmates on move #5 with NxR!

I like this one. However I only found mate in 6 only so far. I will keep trying 🙂
a) 1. e4 f6 2. Nf3 Kf7 3. Ng5+ Kg6 4. d3 Kh6 5. Nf7+ Kg6 6. Nxh8 mate

b) 1. e4 f6 2. Nf3 Kf7 3. Nh4 Qe8 4. Ng6 d6 5. any Be6 6. Nxh8 mate

In a) the problem is that White needs 4 moves to move the knight to h8 so there is no time left for playing d3.
In b) the problem is that Black needs a 5th move to block all his kings escaping squares.

Originally posted by jfkjmh
1. e2-e4 ...
White checkmates on move #5 with NxR!

Are you sure that White checkmates? I have a hunch that problem you're trying to quote is this one:
http://www.chessatwork.com/board/showthread.php?threadid=19617

If so, the solution is:

Originally posted by BigDoggProblem
How about 1.e4 Nf6 2.Qe2 (2.f3) 2...Nxe4 3.f3 (3.Qe2) 3....Ng3 4.Qxe7+ Qxe7+ 5.Kf2 Nxh1#.

Pity about the dual on move 2. Otherwise, a nice problem.