Is it alive, dead or it's seki?

cobrahc · Post by **cobrahc** » Tue Jul 28, 2015 9:57 am

Hi there,

The following position appeared in my last game.
I though my group was alive because it had 2 eyes, my opponent though it was seki... and the automatic score though it was dead.

What's the status of this white group?

Click Here To Show Diagram Code: [go]$$W $$ ---------------- $$ - . . . . . . . $$ - X X X . . . . $$ - O O X . . . . $$ - . O X X . . . $$ - O O O X . . . $$ - X X O X . . . $$ - . X O X . . . $$ - X . O X . . . $$ - O O O X . . . $$ - X X X X . . . $$ - . . . . . . .[/go]

leichtloeslich · Post by **leichtloeslich** » Tue Jul 28, 2015 10:06 am

Show me the sequence to kill the inside black stones and I'll believe you that it isn't seki.

schawipp · Post by **schawipp** » Tue Jul 28, 2015 10:11 am

If you claim an area as white territory, you must be able to kill all black stones, which are located inside. Is this the case in your example?

skydyr · Post by **skydyr** » Tue Jul 28, 2015 10:12 am

White can't kill the stones because he'll be down to one liberty when he approaches. Black can't fill because he'll lose a liberty as well.

Therefor: seki.

Cassandra · Post by **Cassandra** » Tue Jul 28, 2015 10:17 am

Click Here To Show Diagram Code: [go]$$W $$ ---------------- $$ - . . . . . . . $$ - X X X . . . . $$ - O O X . . . . $$ - . O . X . . . $$ - O O O X . . . $$ - X X O X . . . $$ - . X O X . . . $$ - X 1 O X . . . $$ - O O O X . . . $$ - X X X X . . . $$ - . . . . . . .[/go]

You should have given atari at Black's four stones, latest before the very last outside liberty of your own group disappeared.

Click Here To Show Diagram Code: [go]$$W $$ ---------------- $$ - . . . . . . . $$ - X X X . . . . $$ - O O X . . . . $$ - . O 2 X . . . $$ - O O O X . . . $$ - X X O X . . . $$ - 3 X O X . . . $$ - X O O X . . . $$ - O O O X . . . $$ - X X X X . . . $$ - . . . . . . .[/go]

You willh have to take Black's stones off the board.

Click Here To Show Diagram Code: [go]$$W $$ ---------------- $$ - . . . . . . . $$ - X X X . . . . $$ - O O X . . . . $$ - . O X X . . . $$ - O O O X . . . $$ - . . O X . . . $$ - O . O X . . . $$ - . O O X . . . $$ - O O O X . . . $$ - X X X X . . . $$ - . . . . . . .[/go]

Now you have three eyes, five points of territory, and four prisoners.

Mike Novack · Post by **Mike Novack** » Tue Jul 28, 2015 10:20 am

cobrahc wrote:Hi there,

The following position appeared in my last game.
I though my group was alive because it had 2 eyes, my opponent though it was seki.

However possibly misunderstanding something.

A group in seki isn't dead, it is alive in seki. You two weren't in diagreement. If there is a seki situation, there will always be two eyes.

Here both the white group and the black group are alive in seki.

cobrahc · Post by **cobrahc** » Tue Jul 28, 2015 10:26 am

Looks like I'm so used with the "two-eyes" white is alive.. that I forgot that it doesn't mean the black stones inside are dead.
Actually, I never though about this possibility.. for some reason I assumed that any group without eyes inside my "2-eyed" group were dead.
Now, thinking about it, I'm glad this situation happened in my game.

jdl · Post by **jdl** » Tue Jul 28, 2015 10:41 am

Mike Novack wrote:If there is a seki situation, there will always be two eyes.

I don't understand this statement. The first example on Sensei's Library seems to show the opposite.

http://senseis.xmp.net/?Seki

Pio2001 · Post by **Pio2001** » Thu Jul 30, 2015 2:34 pm

Indeed, it happened to me too. I had two completely separated eyes, so I was alive.
I was playing against the software Many Faces of Go. I was used to see it throw stones uselessly, so I didn't bother, until I told myself "hey, this group is running out of liberties, time to capture the dead stones... WTF ?!?"

The possibility to make such a seki with three stones around a corner is common :

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Is it alive, dead or it's seki?

Is it alive, dead or it's seki?

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Re: Is it alive, dead or it's seki?

Re: Is it alive, dead or it's seki?

Re: Is it alive, dead or it's seki?

Re: Is it alive, dead or it's seki?

Re: Is it alive, dead or it's seki?

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