All you need to know about Carpenter's Square - 14
Diagram 14.1: White to play
We now move on to shapes with the 4-4 points occupied by white. These are much weakened shapes.
Diagram 14.2: Even weaker shape
We will not discuss this even weaker shape as black is clearly dead.
Diagram 14.3: Solution 1
is simple and effective. Black clearly has insufficient eyespace. If 
plays 'a', white still replies at 
to win the capturing race.
Diagram 14.4: Solution 2
works too. The marked stone 
forces black to fill his own eyespace at 
so the whole corner is dead.
Diagram 14.5: Extra hane
If black has the extra 
stone, white can still use Diagram 14.4 to kill the corner. This diagram shows how white would respond to 
from the other side. is good. Black cannot play 'a' because of insufficient eyespace. If black plays and *b8*, white wins the capturing race by one liberty.
Diagram 14.6: Extra liberty
Even if black has an extra liberty at 'a', white can continue to use Diagram 14.4. In case black plays , white can make it a 'Golden Chicken Standing on One Leg' to kill the corner as shown here.
Conclusion: this corner shape is too weak to survive even with either of the two favorable conditions.
