Four die, six live

Four die...

This is a continuation of the discussion given in Six die, eight live (on the second line,) but applies to a group on the second line that has a base at the edge of the board.
DIAGRAM 1
Here White will die even if White plays first.
DIAGRAM 2
1 is the only move, and Black 2 will kill the group. Of course, if Black ignores White 1, White can play at 2 and make two eyes.

...six live

Six with a base in the corner is unconditionally alive.
DIAGRAM 3
If Black tries to reduce the white eye-space, white will still have four in a row.
DIAGRAM 4

and how about five?

DIAGRAM 5
When there are five stones, if White plays first, White will live: if Black plays first, White will die. If you have read the "Six die, eight live" article you can work this out for yourself.

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