Deductive Puzzle #40

There are three White Knights on the board.... but still 8 pawns!?!? Obviously, one of the Knights can not be real! Which one is it?

Know that both black and white still can castle in the future.

Is there a fake knight or a fake pawn?

Haha... good point, I completely forgot to specify. It is the Knight that is fake.

I'm having quite a bit of difficulty with this one.  I've reached the conclusion that either the diagram is incorrect or I have some faulty reasoning.  I'll post my reasoning so far to see if anyone can poke any holes in it.

Black is missing 3 pieces (Rook, Queen, g7 pawn), White is only missing 1 (Queen).  I am assuming here that only one of the White Knights is faked, as this is implied by the wording of the problem (perhaps that is the flaw in my reasoning?).

Since White is only missing the one piece, it must have been captured on b6.  However, it could not have escaped until the capture on c3 is made.  Now, it could not have been the Black Queen that was captured here because it could not have escaped until cxb6 occurred.  It was also not the Rook that was captured here as it could not have escaped its prison of a7-a8-b8.  Thus, it must have been the g7 pawn which was captured on c3.

However, consider that we have already accounted for all of White's missing pieces.  Thus, the g7 pawn never left the g-file.  For it to have made it to c3, then, it must have promoted.  In order to promote, the g2 pawn would have to have moved out of the way.  However, there exists no other Black piece for this pawn to have captured to bring it to h3.

The only way out of this is to assume that only one White Knight is truly on the board.  This Knight captured the Rook, likely on a8, then was itself captured on b6.  This let the Black Queen out.  Now, if the Black Queen were captured on c3, then the White Queen could go let itself be captured on h3 by the g7 pawn, which White then recaptured with the g2 pawn.  In this case, since the f3 push is not required by this point - and could not have occurred before this point due to the position of the light-squared Bishop - there is no way to say which Knight was the one captured on b6.

Cute, Nietzsche. The b1 knight is fake.

Black bishop captured on c3, white queen captured on b6, black queen captured on h3, black pawn promoted to bishop.  White pawn needs to move to f3 to let bishop out to get to g7, so knight has no way of getting to g1.

Thanks, Jatsu.  The flaw in my logic was that I was assuming the g7 pawn wasn't still on the board somewhere.  As a side note, the pawn could not have promoted to a Knight because it could not have gone to h3 or e2 due to the pawns and could not have gone to f3 due to a check - forcing the White King to move.