Impossible Chess Puzzle???

Solve this mate in 1! It's white to move.

b8=Q checkmate

The answer is...

(Do you want me to reveal the answer???????????????????????????)

Kxb8

I'm not quite sure when the rules of chess changed, but back then the rules said "pawns may promote to any piece other than pawns and kings", which doesn't exclude promoting to the opposite color. 1. b8=bN#!!, promotion to black knight, is the key.

Of course, now it's illegal, and I believe there is no mate in 1 here.

 Oh yeah. I guess there is no mate in one.

It's always... interesting... to see different people posting the same version over and over again. Since they are classics, people will see them once, see them again and then get bored.

Therefore I suggest making your own versions!

That one has 2 solutions, though

b8=Q# and b8=B#. The first one is actually impossible. I think.

Nope. Only one solution. Did you notice the pin?

1. bxa8=bR#!

I agree

geez,i thought of bxa8=bN. But that would be check, missed that.

This one does violate the rules, it is b8=BN#!? Good job choatic_iak

Another one: 

That one by Tim Krabbe. Mainline 1. e7! Kxf3 2. e8=R!! Kg2 3. 0-0-0-0-0-0#!!!. 1...Kxf3 2. e8=R d4 3. 0-0#; 1...Kd3 2. e8=R Kc2 (2...d4 3. 0-0-0#) 3. 0-0-0-0-0-0#.

It was composed to highlight an omission (at the time) in the FIDE Laws of Chess. The castling clause was subsequently amended to require the king and rook to be on the same rank (although interestingly it still doesn't explicitly specify an original rook required, the possibility of a black pawn promoting to white rook is covered by the clause on promotion instead.)

Can I try 1?

Cooked, both 1. 0-0-0# and 1. Rd1# mates.

Inspired from above:

O-O-O Kc3 Qb2#. This is fun!

gzknight20 you can't promote a white pawn to a black piece.