# A retro classic

BigDoggProblem
Posers and Puzzles 30 Mar '05 23:01
1. BigDoggProblem
30 Mar '05 23:01

Where is the white King?
(The only hint is that the position must be legal.)
2. theangrystudent
I am MIGHTY!
30 Mar '05 23:282 edits
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
3. BigDoggProblem
31 Mar '05 00:18
Originally posted by theangrystudent
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 ...[text shortened]... s also impossible since there is a black rook sitting on b5.

So the answer is.... NO SOLUTION
Wrong!
4. theangrystudent
I am MIGHTY!
31 Mar '05 00:21
Originally posted by BigDoggProblem
Wrong!
Do I have an error in logic, or am I not seeing an option?
5. BigDoggProblem
31 Mar '05 00:55
Originally posted by theangrystudent
Do I have an error in logic, or am I not seeing an option?
An error in logic.
6. 31 Mar '05 01:051 edit
Maybe we are playing right to left and left to right. That is the only way the bishop could have got there. ie by a pawn being promoted.

And why didn't the black rook take it? becase the king was guarding it.
7. Bowmann
Non-Subscriber
31 Mar '05 01:17
c3.
8. Palynka
Upward Spiral
31 Mar '05 01:20
From b3? How could black check the king with both bishop and rook?

ðŸ™„ðŸ™„ðŸ™„ðŸ™„ðŸ™„ðŸ™„
9. Bowmann
Non-Subscriber
31 Mar '05 01:24
Originally posted by Palynka
From b3? How could black check the king with both bishop and rook?

ðŸ™„ðŸ™„ðŸ™„ðŸ™„ðŸ™„ðŸ™„
By capturing a pawn.
10. Palynka
Upward Spiral
31 Mar '05 01:29
Thanks, but i still can't see how... ðŸ™„
11. Bowmann
Non-Subscriber
31 Mar '05 01:321 edit
Originally posted by Palynka
Thanks, but i still can't see how... ðŸ™„
You will eventually. Or ask BigDog...nicely.
12. 31 Mar '05 01:35
Can you go through that one more time bowie. I missed the first bit?
13. The Plumber
Leak-Proof
31 Mar '05 01:371 edit
OK, I give. If there's an error in this logic please identify the step. (I assume that the King is the only missing piece - if there are other missing pieces, there are multiple correct answers).

1 - If it is white's move, the King must be at B3, or else Black ended his move in check, not a legal position.
2 - If the white King is at B3, there is no possible prior move for Black, since both hisi bishop and rook are checking white, and there is no way one of them could have move in such a way as for both of them to check white simultaneously.
3 - Therefore it is not white's move.
4 - If it is black's move, the white King must be somewhere other than G6 or F5, because in both of those locations he is in check and he cannot end his turn in check.
5 - Therefore Black is in check.
6 - The preceding move by white left Black in check. The only way possible for that is either the Bishop moved to where it is, or some other piece moved out of B3 or C2 to leave Black in check by the Bishop.
7 - The only places that the Bishop could have move from are B3 or C2, and in both cases, Black would have already have been in check. Therefore the white's last move was not the Bishop, and must have been the King vacating B3 (C2 not possible since it is adjacent to Black's King).
8 - If white's king just moved from B3, then we are left with the same conflict previously dicsussed in step 2.
9 - Hence, there is no solution.

14. Bowmann
Non-Subscriber
31 Mar '05 01:38
Originally posted by jimslyp69
Can you go through that one more time bowie. I missed the first bit?
Am I allowed to? It isn't my problem! (Don't take that the wrong way.)
15. Bowmann
Non-Subscriber
31 Mar '05 01:41
Originally posted by The Plumber
1 - If it is white's move, the King must be at G6...
You could start by putting your board the right way round.