Kirby wrote:Thanks for the video, topazg. You gave some clear explanations. A lot of what you said pretty much makes sense to me, but I had one question about a comment that you made.
In particular, you mentioned the "Cap and knight's move jump" as a way to attack the group. It seems like a good heuristic. However, I'm not clear why the knight's jump is superior to pressing white in the following diagram:
$$c
$$ ---------------------------------------
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O X O O X . . . . . . . . . . . . |
$$ | . . . X O X X . . . . . . . X X O . . |
$$ | . . O O X O X O O , X . X X O X O . . |
$$ | . . O X X . X . . . . X . X O X . . . |
$$ | . . . . . . . . O . . . X O O O O . . |
$$ | . . . . . . . . . O . . . O . . . . . |
$$ | . . . X . . . . X a . . . . . . . . . |
$$ | . . . . . . . . . . B . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | X . X X X . . . . . . . . . . . . . . |
$$ | X . . . X O . . . . . . . . . . X . . |
$$ | . X X X O . O . . , . . . . . , . . . |
$$ | . O O X O O . . . . . . . . . O . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$c
$$ ---------------------------------------
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O X O O X . . . . . . . . . . . . |
$$ | . . . X O X X . . . . . . . X X O . . |
$$ | . . O O X O X O O , X . X X O X O . . |
$$ | . . O X X . X . . . . X . X O X . . . |
$$ | . . . . . . . . O . . . X O O O O . . |
$$ | . . . . . . . . . O . . . O . . . . . |
$$ | . . . X . . . . X a . . . . . . . . . |
$$ | . . . . . . . . . . B . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | X . X X X . . . . . . . . . . . . . . |
$$ | X . . . X O . . . . . . . . . . X . . |
$$ | . X X X O . O . . , . . . . . , . . . |
$$ | . O O X O O . . . . . . . . . O . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
I agree that it looks like the marked stone will be effective. However, what is wrong with a move like "a"? The move that feels most natural to me is "a", and I am curious about its disadvantages.
Quick first question to guide you in dealing with how to handle the opponents' weak groups:
Are you attacking it, or fighting with it?
If you're attacking, then you have no weak groups and you're just making profit. Be fast, outside, stay ahead, gain profit, leave some weakness for future exploitation.
If you're fighting, then you also have a weak group, the two of you are in a liberty battle, and you'll be lucky if you make it out alive. Take liberties, increase your own, push to get out, make bad shape, you don't care what happens as long as YOU DON'T DIE!
Let's compare two diagrams:
$$c
$$ ---------------------------------------
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O X O O X . . . . . . . . . . . . |
$$ | . . . X O X X . . . . . . . X X O . . |
$$ | . . O O X O X O O , X . X X O X O . . |
$$ | . . O X X . X . . . . X . X O X . . . |
$$ | . . . . . . . . O . . . X O O O O . . |
$$ | . . . . . . . . . O . 2 a O . . . . . |
$$ | . . . X . . . . X . . c b . . . . . . |
$$ | . . . . . . . . . . 1 . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | X . X X X . . . . . . . . . . . . . . |
$$ | X . . . X O . . . . . . . . . . X . . |
$$ | . X X X O . O . . , . . . . . , . . . |
$$ | . O O X O O . . . . . . . . . O . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$c
$$ ---------------------------------------
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O X O O X . . . . . . . . . . . . |
$$ | . . . X O X X . . . . . . . X X O . . |
$$ | . . O O X O X O O , X . X X O X O . . |
$$ | . . O X X . X . . . . X . X O X . . . |
$$ | . . . . . . . . O . . . X O O O O . . |
$$ | . . . . . . . . . O . 2 a O . . . . . |
$$ | . . . X . . . . X . . c b . . . . . . |
$$ | . . . . . . . . . . 1 . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | X . X X X . . . . . . . . . . . . . . |
$$ | X . . . X O . . . . . . . . . . X . . |
$$ | . X X X O . O . . , . . . . . , . . . |
$$ | . O O X O O . . . . . . . . . O . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
White almost connected, but he can still be cut. Maybe black decides not to right now, but even so the possibility is looming over White's head, oppressing his choices until something happens to change it.
$$c
$$ ---------------------------------------
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O X O O X . . . . . . . . . . . . |
$$ | . . . X O X X . . . . . . . X X O . . |
$$ | . . O O X O X O O , X . X X O X O . . |
$$ | . . O X X . X . . . . X . X O X . . . |
$$ | . . . . . . . . O . . . X O O O O . . |
$$ | . . . . . . . . . O 2 4 a O . . . . . |
$$ | . . . X . . . . X 1 3 c b . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | X . X X X . . . . . . . . . . . . . . |
$$ | X . . . X O . . . . . . . . . . X . . |
$$ | . X X X O . O . . , . . . . . , . . . |
$$ | . O O X O O . . . . . . . . . O . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$c
$$ ---------------------------------------
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O X O O X . . . . . . . . . . . . |
$$ | . . . X O X X . . . . . . . X X O . . |
$$ | . . O O X O X O O , X . X X O X O . . |
$$ | . . O X X . X . . . . X . X O X . . . |
$$ | . . . . . . . . O . . . X O O O O . . |
$$ | . . . . . . . . . O 2 4 a O . . . . . |
$$ | . . . X . . . . X 1 3 c b . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | X . X X X . . . . . . . . . . . . . . |
$$ | X . . . X O . . . . . . . . . . X . . |
$$ | . X X X O . O . . , . . . . . , . . . |
$$ | . O O X O O . . . . . . . . . O . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Ok, white connected. Still cut later at A, B, C, yes?
Not exactly the same situation. Have you read Otake Hideo's book, Opening Moves Made Easy (or something like that?) - he (or the translator) came up with a good name for this sort of situation: a family feud.
$$c
$$ ---------------------------------------
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O X O O X . . . . . . . . . . . . |
$$ | . . . X O X X . . . . . . . X X O . . |
$$ | . . O O X O X O O , X . X X O X O . . |
$$ | . . O X X . X . . . . X . X O X . . . |
$$ | . . . . . . . . O . . . X O O O O . . |
$$ | . . . . . . . . . O O O 1 O . . . . . |
$$ | . . . X . . . . X X X 2 3 . . . . . . |
$$ | . . . . . . . . . . . 4 . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | X . X X X . . . . . . . . . . . . . . |
$$ | X . . . X O . . . . . . . . . . X . . |
$$ | . X X X O . O . . , . . . . . , . . . |
$$ | . O O X O O . . . . . . . . . O . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$c
$$ ---------------------------------------
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O X O O X . . . . . . . . . . . . |
$$ | . . . X O X X . . . . . . . X X O . . |
$$ | . . O O X O X O O , X . X X O X O . . |
$$ | . . O X X . X . . . . X . X O X . . . |
$$ | . . . . . . . . O . . . X O O O O . . |
$$ | . . . . . . . . . O O O 1 O . . . . . |
$$ | . . . X . . . . X X X 2 3 . . . . . . |
$$ | . . . . . . . . . . . 4 . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | X . X X X . . . . . . . . . . . . . . |
$$ | X . . . X O . . . . . . . . . . X . . |
$$ | . X X X O . O . . , . . . . . , . . . |
$$ | . O O X O O . . . . . . . . . O . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
By pushing through, black is forcing white to damage his own group and also the potential in the center. The three stones are no longer thick, they're heavy. So black has no cut.
tl;dr Make light, flexible shape in sente when you can - make slow moves when you must.