J+1 group

    Keywords: Life & Death

Table of contents Table of diagrams
The J+1 group.
Hane.
Placement.
Another placement.
Endgame play.
Sente.
Seki.
The J+1 group with descent.
Tesuji.
White is dead.

J+1 group

[Diagram]
The J+1 group.  

The J+1 group on its own is unconditionally alive.

[Diagram]
Hane.  

If B1 makes a hane, W2 lives.

[Diagram]
Placement.  

The placement at B1 is answered by W2.

[Diagram]
Another placement.  

This placement does not work either.



Endgame play

[Diagram]
Endgame play.  

The usual endgame play by Black is the placement at B1. After W2, B3 makes a descent, and W4 is the only way to gurantee unconditional life. Now B5 makes a throw-in, allowing B7 to capture a stone.

[Diagram]
Sente.  

If W6 decides to capture B5, then B7 is sente.

[Diagram]
Seki.  

If W4 connects, then B5 and B7 makes seki. White is definitely worse off in this diagram.



J+1 group with descent

[Diagram]
The J+1 group with descent.  

When Black descends at black+circle, it changes things. To say the conclusion first, black+circle is sente, so White needs a move at a. (Anonymous: The other descent is not sente.)

[Diagram]
Tesuji.  

The throw-in at B1 followed by the placement at B3 is tesuji. The White corner becomes a bent four in the corner dead shape.

[Diagram]
White is dead.  

Subsequently, W4 and B5 are miai, and W6 and B7 are also miai.


See also


J+1 group last edited by Unkx80 on January 13, 2009 - 18:43
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