Gun Eight

Gun Eight  

When there are no outside liberties, this eight-point large eye shape can be turned into seki or ko with Black to choose. In this position a is the vital point.

Main line  

After , threatens to atari the white stone, (at ) forcing .

Continuation 1A: Sente seki  

then makes the position seki.

Continuation 1B: Seki ( tenuki)  

Black can tenuki and then on its own also makes a seki. After , is dame. Under area scoring it is worth one point to the player who plays it. Under territory scoring it is no points for either player.

Seki is the usual result, but there is a throw-in ko.

Continuation 2: Ko for black  

If Black is ko master than he can throw in a stone at and make a two-stage ko. Because Black needs two big ko threats more than White, this ko favors White, so Black will usually make seki.

Continuation 3: Ko for White ( tenuki)  

If Black plays elsewhere tenuki after in the first diagram, and White is ko master White can also make a two-stage ko.

Variation at 2: seki  

This is a more straightforward way of reaching seki. Here and are miai : / also reaches seki.

How about this Black 2  

Was puzzeling with this shape and

How about this Black 2? It also only seems to result in an seki

and are miai (can be exhanged) It even looks that Black can tenuki after

Gun Eight with outside liberties  

As soon as there is an outside liberty, this shape is alive with 7 points.

Gun Eight with outside liberties  

Thanks to the outside liberty, Black can atari at . Without that extra liberty, puts himself into atari.