Originally Posted by youtalkfunny
I give you this bio because I find it amazing that, in all that time, there was a flaw in my knowledge of the rules! For some reason, I was under the impression that castling was not allowed if any of the squares between the rook and king were under attack (in the OP's screen shot, b1 is vulnerable to black's rook).
If it helps, you're not alone.
"from Catastrophe in the Opening by James Plaskett..
Korchnoi went up to arbiter Alberic O'Kelly and asked if it was legal for him to castle when his rook was attacked. The GM assured him that it was. Korchnoi wrote that in the thousands of games that he had played up until then, there had simply never yet arisen a situation like that, and he was not sure that he understood the rules of the game correctly."
And if you don't know who Korchnoi is, by the time that game was played, he had already won 4 Soviet Championships, and according to chessmetrics.com he was rated #2 in the world then.