I reverted to the position in the video after move 4.
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[go]$$c 1: Black to move.
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$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , . . b . . , . . . . . X . . . |
$$ | . . . a . . . . . . . . . . . . . . . |
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$$ | . . . O . . . . . , . . . . . X . . . |
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$$ ---------------------------------------[/go]
Black now has a choice to focus on the upper side or the left side.
If black wants to focus on the upper side, black could play at G16 at this moment, which could lead to this continuation, which is a semi-joseki (perhaps a bit slack for black, though):
- Click Here To Show Diagram Code
[go]$$c 2: Black focusses on the upper side.
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$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , . . 1 . . 3 . . . . . X . . . |
$$ | . . . 2 . . . . . . . . . . . . . . . |
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$$ | . . . O . . . . . , . . . . . X . . . |
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$$ ---------------------------------------[/go]
If black wants to focus on the left side, black usually plays D15 instead of G16. Now it's white's turn. White could focus on taking the corner with a move at C15:
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[go]$$c 3: White focusses on the corner territory.
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$$ | . . 2 1 . . . . . . . . . . . . . . . |
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$$ | . . . O . . . . . , . . . . . X . . . |
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$$ ---------------------------------------[/go]
This white move allows black to switch his focus to the upper side:
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[go]$$c 4: White focusses on the corner and black focusses on the upper side.
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$$ | . . . O 5 . . . . . . . . . . . . . . |
$$ | . . 4 3 . . . . . . . . . . . X . . . |
$$ | . . 2 1 . . . . . . . . . . . . . . . |
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$$ | . . . O . . . . . , . . . . . X . . . |
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$$ ---------------------------------------[/go]
White can also focus on making potential on the left and / or upper side with a pincer move instead of C15.
If white plays a 2-space high pincer, black plays the large knight move (when D4 is a white stone) and then white attaches at E15, so we arrive at this position (I assume that this is white's plan when he plays the 2-space high pincer):
- Click Here To Show Diagram Code
[go]$$c 5: White plays a 2-space high pincer to fight.
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$$ | . . . , . . 3 . . , . . . . . X . . . |
$$ | . . . 1 4 . . . . . . . . . . . . . . |
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$$ | . . . 2 . . . . . . . . . . . . . . . |
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$$ | . . . O . . . . . , . . . . . X . . . |
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$$ ---------------------------------------[/go]
Now it's black's turn. Now you suggest that black wants to switch focus to the upper side.
With go, the devil is in the details. So my question is: How?
If you see a black continuation from diagram 5 that takes the upper side in a better way than diagram 2, please share it. If it is convincing, you have found a new joseki variation.
So what continuation do you have in mind from diagram 5 to use D15 as a decoy to take the upper side (instead of black E14 to use G16 as a decoy to take the upper left corner)?
Black K16 perhaps?
- Click Here To Show Diagram Code
[go]$$c 6: Is this continuation feasible for black?
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$$ | . . . , . . 3 . . 5 . . . . . X . . . |
$$ | . . . 1 4 . . . . . . . . . . . . . . |
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$$ | . . . 2 . . . . . . . . . . . . . . . |
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$$ ---------------------------------------[/go]
When evaluating diagram 6, it's important to consider that it's white's move now and white will probably play a move to attack black's stone at D15. Can white kill it? I would consider white continuations at D16, E16 or D14, but it looks difficult for white to secure the whole upper left as territory.