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        riddles >> easy >> Claustrophobic King (Chess)
        
(Message started by: ThudnBlunder on Jan 22^nd, 2011, 7:41pm)

Title: Claustrophobic King (Chess)
Post by ThudnBlunder on Jan 22^nd, 2011, 7:41pm

In the diagram below, if the knight cannot move how many legal moves does Black require to capture it with his king?
EDIT: Oh, the pawns can't move either.

Title: Re: Claustrophobic King (Chess)
Post by rmsgrey on Jan 22^nd, 2011, 10:18pm

Assuming there's a white king moving between g8 and h8 (or otherwise staying out of the way), I'd say [hide]5[/hide] black moves:

[hideb]promote f pawn, move bishop g1-e3, king goes h2-g1-f2xe1[/hideb]

I'm uncomfortable with the idea of evaluating legal moves when one side has no king and makes no moves - is it legal for black to take a second move before white takes a move? If the knight can't move, is it still illegal to move the black king to g2?

Simpler to assume the white king meanders idly without getting involved...

Title: Re: Claustrophobic King (Chess)
Post by ThudnBlunder on Jan 22^nd, 2011, 10:34pm

Duh, sorry the Black pawns cannot move either. :-[ Thanks, now corrected.
Black merely shuffles his pieces in order for his king to escape the corner.
There is no White king.

I should be more careful not to sacrifice clarity for brevity. ::)

It is possible I have posted this previously. :-/

Title: Re: Claustrophobic King (Chess)
Post by towr on Jan 23^rd, 2011, 1:18am

[hide]7[/hide], looks like.

Title: Re: Claustrophobic King (Chess)
Post by Three Hands on Jan 23^rd, 2011, 6:04am

As the black king cannot legally move to g2 due to the threat of the knight, I make it [hide]28[/hide] moves...

EDIT: Before I forget the sequence:

[hide]Bg2-f1, Rg3-g2, Kh2-g3, Bg1-h2, Rg2-g1, Bf1-g2, Rg1-f1, Bh2-f1, Rh1-h2, Bg2-h1, Rh2-g2, Kg3-h2, Rg2-g3, Bh1-g2, Kh2-h1, Bg1-h2, Rf1-g1, Bg2-f1, Rg3-g2, Bh2-g3, Rg2-h2, Rg1-g2, Kh1-g1, Rh2-h1, Rg2-h2, Bf1-g2, Kg1-f1, Kf1xe1[/hide]

Title: Re: Claustrophobic King (Chess)
Post by towr on Jan 23^rd, 2011, 6:48am

Ah, yes, I forgot about that. But then, despite my father's protestations to the contrary, I'm terrible at chess.