Re: computer-go: What makes a ladder

[Nick Wedd <Nick@xxxxxxxxxxxxx>]

Njoroge <Njoroge@xxxxxxxxxxxxxxxxx> writes
>The ladder fails if:
>    - L2 is found to be a black stone
>    - O has less than 2 liberties
>
>The ladder is successful if:
>    - L2 is either outside the board or is a white stone
>    - L2 is a black stone with only 2 or less liberties
>    - L2 is a black stone on the edge with only 3 or less liberties
>    - L2 is a black stone in the corner with only 4 or less liberties

>Is this always true?

No.  Two similar positions, upper edge, Black to play:

 -.-.-.-.-.-.-.-.-.-.-       -.-.-.-.-.-.-.-.-.-.-
  . . . . . . . . . .         . . . . . . . . . . 
  . . . . . . . . . .         . . . . . . . X . . 
  . . . . . . X . . .         . . . . . . . . . . 
  . O . . . . . . . .         . O . . . . . . . . 
  . O X O . . . . . .         . O X O . . . . . . 
  . . O . . . . . . .         . . O . . . . . . . 
  . . . . . . . . . .         . . . . . . . . . . 

  Black can save the          Black can't save the 
  ladder stone.               ladder stone.

Nick
-- 
Nick Wedd    nick@xxxxxxxxxxxxxxxxx