Using the old rules

Logic Level 2

This game was played when it was legal to promote to a piece of the opposite color.

Castling in chess is legal when (a) neither the King or the Rook has moved, (b) the King is not in check, and (c) the King does not pass over a square which would put him in check.

We are given that it is Black's move and that Black has never moved his King. Can Black castle?

No Yes

Denton Young by Denton Young , 47, USA

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Denton Young
Mar 27, 2020

White's last move had to be a promotion of a Pawn to the Black Rook. So the Rook has not moved (since it JUST appeared on the board), we are given the King has not moved, and the other two conditions are easily met. Black can therefore castle.

0 Helpful 0 Interesting 0 Brilliant 0 Confused

But what if the rook moved and then retreat to his original position and was never promoted?

Kano Boom - 1 year, 2 months ago

Log in to reply

Retrograde analysis shows that the Rook HAS to be newly promoted. The White King and Pawns can't have made the last White move, so it must have been a Pawn promoting to the Black Rook.

Denton Young - 1 year, 2 months ago

Speaking of retrograde analysis, Raymond Smullyan wrote a couple of excellent books of this type of chess puzzle, including some amazingly complicated ones. I can definitely recommend seeking them out if you liked the logic in this question.

Chris Lewis - 1 year, 2 months ago

Log in to reply

I own them both.

Denton Young - 1 year, 2 months ago

1 pending report

Vote up reports you agree with

×

Problem Loading...

Note Loading...

Set Loading...