Joseki - Invasions Under and Near the Star-Point (Hoshi)

PATTERN TWO
Black has made a one-space
extension from the star-point stone. A
single-handed invasion is unusual, but
it is of course possible.



Dia. 1 (3-3 invasion).
Invading at 1 is the usual approach: it is
the vital point. If Black 2, White 3 makes good shape; if 4, White
lives up to 11.

Dia. 2 (losing points).
Giving atari at 6 before blocking at 8 is
bad. White captures the stone and Black gets no compensation for
his loss.





Dia. 3 (emphasizing the right side).
It's different, however, if Black connects at 1 instead of 8 in Dia. 2. Emphasizing the right
side like this is possible. If Black 3 and 5, White lives up to 6.

Dia. 4 (unreasonable).
Black can also jump down towards the edge with 4. White will seek a base with 5 to 9 and attempting to take away his eye-shape immediately with 10 is unreasonable.
Black collapses after the forced continuation to 19.





Dia. 5 (unsuccessful).
Attaching at 4 is a short-tempered response
to White 3. Black's attempt to kill White with 10 is unlikely
to succeed. White counters with the carefully timed sequence to 23
and is virtually alive. Black has to worry about his weak point at `a'.
Dia. 6 (alternative strategy). Blocking on the inside at 2 is feasible
in some positions. White lives in the corner and Black builds
up outward influence.