Introduction
The lesson video is the following
Main position
In this lesson we have seen how to manage a pincer while approaching a 3-4 corner.
White approach with 1 and black responded with 2. From there, white has two choices that will depend on the ladder shown with circle and potential ladder breaker in the opposite corner.
Ladder is good for white
If the ladder is good for white, then the attachment at 1 is good. The sequence in the next diagram is likely to follow.
In this sequence, white sacrifices the marked stone and live in black corner, breaking into black moyo.
Black overplay
In the previous diagram, it would be bad for black to try to fight with 10.
Indeed, white can calmly turn at 11, threatening to capture and live in the corner. So black must connect, and white can capture the black stones with 13.
The ladder
If black tries to keep things simple and prevent white for invading the corner, then the following sequence should be played.
This is when the ladder comes into play. In this case, as the ladder is good for white, this result is quite satisfactory.
In case black tries to avoid the ladder with the following moves.
Then white can force the sequence in the diagram above and settle on the side. This is quite good for white as he could settle in black moyo.
These sequences are not as good as the main variation for black, so if the ladder doesn’t work, black should avoid playing this way.
Ladder is good for black
If the ladder is good for black, if white tries to play the same sequence as before, black will live in the corner with 6 and as the ladder is bad, white cannot capture the stone at 4. So white is now in big trouble as one of his group will likely die.
Attach from the inside
So instead of the attachment from the top, white can attach from the inside.
If black hane, then white cross-cut and we are back to the previous sequence.
If black extends as in the following diagram.
Then white can easily take the corner from black with the move up to 9.