Chokchoksu (Shortage of Liberty)
This is a capturing method by using shortage of liberties.
White's marked stone has only one liberty.
Of course, Black can capture a White stone with 1, but White saves the three stones with 2.
However, Black 1 captures the four stones by using the shortage of liberties.
If White plays at 1, Black captures the whole chain with 2.
A snapback is the method which captures the opponent stones by sacrificing your stone. In real games, this kind of sacrificing skill is very useful.
Two marked White stones have two liberties.
Black 1 here helps White to save the marked stones with 2.
Black 1 is a good sacrifice . After White 2.
Black captures three White stones with 1.
A net is a capturing method which kills the enemy stone(s), by blocking both directions without filling the liberty directly.
Playing Dansu is not the way to capture the marked White stone.
Black 1 is a good move to capture the White stone.
If White tries to escape with 1, Black blocks at 1.
Up to Black 2, White's group can't escape from the net.
A ladder is a method to capture the opponent's stone(s) by playing Dansu continuously without being captured.
The marked White stone has two liberties, but Black can capture the stone by playing Dansu continuously.
Black 1 is the correct direction to capture a White stone.
This diagram shows a successful ladder.
Black 1 here is wrong. After White 2, Black can't capture the White group.