Originally posted by BigDoggProblem
[fen]8/8/8/1r1b4/B7/8/8/3k4 w - - 0 1[/fen]
Where is the white King?
(The only hint is that the position must be legal.)
Since black is in check, white made the last move.
It wasn't a discovered check because the white king could not have been on either of the two squares seperating the black king and the white bishop.
Also the bishop couldn't have been on a4-d1 diagonal last turn since that would mean that either the black king was in-check last round and didn't move, the king moved into check, or black was able to move a piece and expose himself to check; all of which are illegal options.
Since it is impossible that the bishop was where he is the prior round, he must have moved there. But to do that he must have moved along the a4-e8 diagonal. Unfortunately the bishop moving along that diagonal last round is also impossible since there is a black rook sitting on b5.
So the answer is.... NO SOLUTION