L+1 group
An L+1 group is an L group with a leg. The leg can be at the short side or the long side of the L shape. In both cases the group lives or dies according to who has sente.
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First L+1 group
White can kill by playing hane at . This reduces the shape to the standard L group, which we already know is dead.
First L+1 group, hane on one side
The throw-in at no longer works:
jumps and lives. If
makes a placement,
connects, and White cannot connect at a due to shortage of liberties, otherwise Black captures three to make an eye.
However, White can kill by the hane at followed by the placement at
.
tries to live, but
forces
, so
makes a throw in and kills. Note the importance of the
stone.
First L+1 group, hane on both sides
For hundreds of years or even thousands of years, the first L+1 group with hane on both sides is thought to be alive. However, when the group has no external liberties, White can turn it into a ten-thousand year ko.
Second L+1 group
Second L+1-group, hane one side
The throw-in at doesn't work anymore. Black lives with
: White can not connect at a because Black can capture three to make an eye.
To kill, can go straight to the 2-2 point. After
, Black is dead. See the addendum of the rectangular six in the corner page. As before, the
stone is important.
Second L+1-group, hane on both sides
Second L+1 group, 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.
Something like an L + 1 group
See also: