Is black not surrounding white?

Hi, newbie question here, would appreciate if someone can explain this to me. I’m playing black here and thought that I’ve managed to surround white, but its 2 steps later my black stones on bottom right is dead. :upside_down_face:

1 Like

In a certain sense you have, but in a strictlly go sense, white has 2 empty spaces next to the group on the inside. Those need to not be there in order to capture. The problem is white can capture the inside group if you try, and although you could still try to kill it white is simply faster on the right side.


Curious what happened in-game. I think white needs to kill the top right before capturing the bottom right


What you have on the bottom is an odd corner case called seki in ko

Technically both Black and White are sharing two mutual liberties that neither can play on because the first one to eliminate a liberty dies.

However, the Ko at B1/C1 needs to be resolved before the seki is complete - so it’s kind of like Schrödinger’s cat - both alive and/or dead until that Ko is resolved.

1 Like

I see… i guess it means that the game has to go on for there to be an outcome and i would have lost. Thanks for the explanation! =)

It’s actually a total loss if your opponent knows basic semeai and serial atari. And there is no valid ko threat to speak of if white knows how to answer.

Also, the lower-left black group cannot get two true eyes if white knows how to answer right and kill it. Even if that group lives which requires white to ignore black two moves, the extra move white gets will kill the upper right black, and white would get all the rest while black only gets 2 eyes.


sort of… In some sense the game should not go on as black is already “dead”. But beginners can continue the game because it is a good exercise to see how it actually gets captured.


I agree with Claire. Black is simply dead everywhere on the board.


  1. B5 can never be an eye unless Black can capture A6, and White is not obliged to permit this.

  2. That means that Black is dead on the left side, unless the lower-side group can first be captured.

  3. The upper-right Black group is weaker than the lower-left group, so the semeai will be fought between the lower-side and upper-right groups.

  4. The upper-right group has two liberties.

  5. The lower-side group has four liberties, because White can capture Black’s original inside stones.

  6. Since White can win the semeai, both groups are dead. There is no relevant seki or ko.


(2) capturing (1) and the triangled stones.

1 Like

Yea… I’m playing against the computer so definitely I’m gonna lose haha. Thanks.

Yea pretty much doomed 🥲 Thanks for playing this out.

Nice case of Black surrounding White, but White more effectively surrounding Black.