[Computer-go] Semeai and ko

Jason House jason.james.house at gmail.com
Tue Apr 26 09:59:50 PDT 2011


"Counting Liberties and Winning Capture Races" gives some basics. It's definitely not comprehensive, but it might be a good start.

Sent from my iPhone

On Apr 26, 2011, at 10:52 AM, "Brian Sheppard" <sheppardco at aol.com> wrote:

> I have always found kos in semeais to be bewildering. E.g., I have a hard
> time determining who should win, even with plenty of time to work it out.
> 
> I know one guideline that is close to ironclad: take the ko last. (That is,
> fill other liberties before beginning the ko.)
> 
> But I haven't come across any rules for how to count liberties when a ko is
> involved.
> 
> Can anyone offer guidance on this?
> 
> Thanks,
> Brian
> 
> -----Original Message-----
> From: computer-go-bounces at dvandva.org
> [mailto:computer-go-bounces at dvandva.org] On Behalf Of Rémi Coulom
> Sent: Tuesday, April 26, 2011 6:13 AM
> To: computer-go at dvandva.org
> Subject: Re: [Computer-go] New Crazystone - when again?
> 
> I have similar logic in Crazy Stone, but in this particular case, it does
> not understand the semeai because of the ko. Should be easy to fix.
> 
> Rémi
> 
> On 26 avr. 2011, at 07:53, David Fotland wrote:
> 
>> Many Faces’ old engine counts liberties in semeai that way, including
> approach moves, shared liberties when only one side has an eye, etc.  This
> information is only used in the tree, not the playouts.
>> 
>> David
>> 
>> From: computer-go-bounces at dvandva.org
> [mailto:computer-go-bounces at dvandva.org] On Behalf Of terry mcintyre
>> Sent: Monday, April 25, 2011 10:13 AM
>> To: computer-go at dvandva.org
>> Subject: Re: [Computer-go] New Crazystone - when again?
>> 
>> Rémi:
>> 
>> I also believe it resigned in a lost position. The mistake was S14. It
> should have played J12 or M12 instead, which should lead to a win.
>> 
>> Rémi is correct. 
>> 
>> S14 is an interesting blunder. The preceding T2 move didn't exactly remove
> a direct liberty from white - it allowed the O1 approach move which had
> previously been a self-atari for black. This conforms to a more generalized
> use of the word "liberty" used in some discussions of capturing races. 
>> 
>> Does Bonobot - or any program - maintain a count of "moves needed to
> capture X, including approach moves and throw-ins, etc?"
>> 
>> 
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