Twisted four in the corner
A twisted four which occurs in the corner may not be quite the same as the normal twisted four. The twisted four in the corner follows exactly the same logic as bent four in the corner.
However, unlike the bent four in the corner, Japanese rules does not specify that any group whose eye shape that can be reduced to a twisted four in the corner is automatically dead. That is, the twisted four version of the "bent four in the corner is dead" rule does not apply.
Table of contents | Table of diagrams Fewer than two outside liberties Main line Two outside liberties Main line Main line Not Corner Twisted Four |
1. Fewer than two outside liberties
If there are fewer than two outside liberties, White can turn this position into a ko.
2. At least two outside liberties
If there are at least two outside liberties, Black is alive with three points.
Thanks to the two liberties, Black can play atari at
. Without one of those liberties, he would be putting himself into atari.
3. Endgame implications
When White reduces the outside liberties with ,
makes three points in gote, preventing the ko.
Side note: at a also lives, but is inferior to
because White would have a ko threat at
.
4. Corner Non-Twisted Four
The following is a Twisted Four and is in the corner but is not an example of what is meant by Twisted Four in the Corner. It is alive - a and b are miai:
See also:
Authors