Diagram 1, This was taken from amateur 7d’s games and someone raised a good question: Which is better for Black at A or B here? Obviously Black C is very big if Black gotten sente. Regardless, this lecture is to show the tsumego that appears on the bottom right.
Diagram 2, Black move-1 here is the best answer as Black can initiate the fight at move-7.
Diagram 3, Black move-1 then tenuki to move-3 can get killed without any condition.
Diagram 4, After Black move-1, When White move-2 intended to kill Black can easily get sente at move-3 and move-5. So – Is Black alive at the corner?
Diagram 5, White move-1 is obvious killing move but as Black move-4 is a sente, Black created Thousand-Years KO with move-6.
Diagram 6, What about if White chose to play move-5 instead? Is Black alive or dead at the corner?
Diagram 7, White move-1 then Black-2 creates a soft-KO for Black.
Diagram 8, White has hard time to kill Black in this KO. Is there a unconditional method to kill Black?
Diagram 9 , White move-1 ‘death at hane’ is one most important first-move to kill. Black move-2 is obvious, White must move-3 to kill the eye. After a series of follows-up, Black move-8 confirms Black’s living.
Diagram 10 , Black move-10 captures the 3 stones in sente and make living at move-12.
Diagram 11 – Diagram 12, If White move-5 to reduce liberty space, Black can also throw-in at move-10 then captures at move-12 to make living in sente.
Diagram 13 – Diagram 14, However in this situation, Black move-8 throws-in actually a bad move as the sequence is different from Diagram 11-Diagram 12. After Black captures at move-12 White can captures back at move-13. Black is in check.
Diagram 15, Back to the important question – is Black alive or dead without condition?
Diagram 16 – Diagram 17, White move-5 kills Black unconditionally. So Black is dead.