Gun Eight

    Keywords: Life & Death, Shape

Table of contents Table of diagrams
Gun Eight
Main line
Continuation 1A: Sente seki
Continuation 1B: Seki (B4 [tenuki])
Continuation 2: Ko for black
Continuation 3: Ko for White (B4 [tenuki])
Variation at 2: seki
How about this Black 2
Gun Eight with outside liberties
Gun Eight with outside liberties

1. No outside liberties

[Diagram]
Gun Eight  

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

[Diagram]
Main line  

After W1, B2 threatens to atari the white stone, (at square) forcing W3.

[Diagram]
Continuation 1A: Sente seki  

B4 then W5 makes the position seki.

[Diagram]
Continuation 1B: Seki (B4 tenuki)  

Black can tenuki and then W5 on its own also makes a seki. After W5, square 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.

[Diagram]
Continuation 2: Ko for black  

If Black is ko master than he can throw in a stone at B4 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.

[Diagram]
Continuation 3: Ko for White (B4 tenuki)  

If Black plays elsewhere tenuki after W3 in the first diagram, and White is ko master White can also make a two-stage ko.

[Diagram]
Variation at 2: seki  

This is a more straightforward way of reaching seki. Here B4 and W5 are miai : B5/W4 also reaches seki.


[Diagram]
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

B4 and W5 are miai (can be exhanged) It even looks that Black can tenuki after W3


2. Outside liberties

[Diagram]
Gun Eight with outside liberties  

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

[Diagram]
Gun Eight with outside liberties  

Thanks to the outside liberty, Black can atari at B6. Without that extra liberty, B6 puts himself into atari.


3. Endgame conclusions

When the last outside liberty is taken, the play on the 2-2 is normally a 3 1/2 point gote (Miai Counting).



Gun Eight last edited by SiouxDenim on May 21, 2017 - 13:05
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