Deductive Puzzle #42

There is an officer on the board that is in fact an illusion. Knowing that the royalty has neither under attack nor have they moved, figure out which piece is not real.

The first observation is that white's h1 rook was captured on c6. So, how did it get there? It had to have been captured BEFORE black's a8 rook. That means, black's dark-squared bishop was the first piece captured.

Of course, we all know what this means. For the h1 rook to escape, the f1 bishop can't be in its current location, and yet it cannot move with pawns rooted on g2 and e2. Therefore, the f1 bishop is an illusion- it was captured by a black knight.

EDIT: Sorry if I wasn't too clear. Black's dark-squared bishop was captured on e3, opening the f-file, which can only be used if the f1 bishop is gone, and as it can't move at that point it must have been captured.

RR: There are still pawns on g2 and e2. The only piece that can be captured at the start is black's black-squared bishop, which MUST have been captured on e3 by the f-pawn.

No, not his black bishop, his black-squared bishop! Read more carefully! f3 is a white square!! *Nytik sighs.*

OK. Take a look at the position in the original post. Black still has his white-squared bishop, right? f3 is a white square.

Knowing that none of the royalty has been under attack means that none of the captures on c6, e3 or f3 can have been knights.

Neither of Black's Queen-side rook or light-squared bishop could have escaped before the capture on c6 an similarly Neither of White's King-side rook or light-squared bishop could have escaped before the capture on f3 which leaves us with a bit of a catch 22.

The only way to resolve this is to surmise that White's light-squared bishop was in fact captured on it's starting square by a Knight and it was in fact the capture of Black's dark-squared bishop on e3 that loosed White's King-side rook.  Once the rook was free it was captured on c6, which allowed Black's rook to escape and eventually be captured on f3.

Therefor, it must be White's light-squared Bishop that is the illusory piece.

Do another!

The only way for White's bishop to be able to get out of the way is of the capture on f3 cleared a path for it to do so?  But what then was captured on f3?  Not a knight, as that would have put the King in check which we know hasn't happened.  So one of Black's rook or a light sqaured bishop then?  But what was captured on c6 to allow them to escape?  Again, not a knight as that would have put the Queen under attack....

This is why it has to be as Nytik described.

How do you know that White's light squared bishop was captured?

It's all explained above.  The alternative is an impossible position with the capture of a piece required on one of the two sides before that piece could have escaped.

 Thank you for explaining. I understand now.