L+1 Group / Leg on the Short Side

Sub-page of L1Group
[Diagram]
Short L+1 group  

An Short L+1 group is an L group with a leg on the short side.

A similar group exsst with the leg at white+triangle (the long side) this is then the L1group/legonthelongside

If there are legs at both sides it is the L+2 group.

Both L+1 groups lives or dies according to who has sente.


Table of contents

[Diagram]
Short L+1 group  

If the leg is on the other side, again the position depends on who has sente.


Black lives

[Diagram]
Black lives  

Now the 2-2 point is the vital point for Black.

White kills

[Diagram]
White kills  

Again, reducing Black to a basic L group by a hane, kills the corner.


hane on one side

[Diagram]
Short L+1-group, hane one side  

The hane at black+circle may give some help in living.

[Diagram]
White cannot kill this way  

The throw-in at W1 doesn't work anymore. Black lives with B2: White can not connect at a because Black can capture three to make an eye.

[Diagram]
White kills  

To kill, W1 can go straight to the 2-2 point. After W7, Black is dead. See the addendum of the rectangular six in the corner page. As before, the white+circle stone is important.


hane on both sides =

[Diagram]
Problem  

The two hane stones give some degree of security.

[Diagram]
Solution  

The attachment at W1 leads to ko.


Wwak leg =

[Diagram]
Weak leg  

The second L+1 group with a weak leg is also unsettled. White can kill at a or Black can live by playing at a.



From L+1 group / discussion

[Diagram]
Black lives 2  

Erock: Can Black also live by playing the 1-2 point?

[Diagram]
Black gives white an extra ko threat  

Answer to Erock: Jared Beck: In "Black lives 1" black lives, and white has 3 ko threats for a later time. In "Black lives 2" black also lives, but white has 4 ko threats.

[Diagram]
Or Black loses a couple points  

Jared Beck: If Black chooses to give up a few points, he doesn't have to suffer the burden of a fourth ko threat.

Jared Beck: Please double-check this, I just looked at it briefly.

[Diagram]
1-2 point  

Chris Hayashida: The problem with the 1-2 point is descending on both sides (marked stones) threatens to kill the group. This isn't the case if black+circle was played correctly at the 2-2 point. Black cannot play at a for his second eye since it is self-atari.



[Diagram]
White kills  


See also:


L+1 Group / Leg on the Short Side last edited by MrTenuki on January 5, 2012 - 20:22
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