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Shimari invasion
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Author:  oca [ Sat Mar 29, 2014 11:05 am ]
Post subject:  Shimari invasion

Hello,

I 'm looking for some insight on this situation, where :w1: invade black shimari
Click Here To Show Diagram Code
[go]$$W
$$ ----------------+
$$ . . . . . . . . |
$$ . . . 3 . . 7 9 |
$$ . , 4 B 1 5 6 8 |
$$ . . . . 2 B . . |
$$ . . . , . . . . |
$$ . . . . . . . . |[/go]


I came with this sequence, but then white can make two eyes what ever I try.
Is there a better way for black to handle the invasion ?

Author:  EdLee [ Sat Mar 29, 2014 11:41 am ]
Post subject:  Re: Shimari invasion

Hi oca,
oca wrote:
Click Here To Show Diagram Code
[go]$$W
$$ ----------------+
$$ . . . . . . . . |
$$ . . . 3 . . 7 9 |
$$ . . 4 B 1 5 6 8 |
$$ . . . . 2 B . . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]
A great deal depends on both the local and global situations.

For a starter, your :b8: is a common beginner mistake, standard bad habit -- you force :w9: to be sente.
Just connect directly is better (then :w9: is gote):
Click Here To Show Diagram Code
[go]$$W
$$ ----------------+
$$ . . . . . . . . |
$$ . . 0 3 . . 7 9 |
$$ . . 4 X 1 5 6 . |
$$ . . . . 2 X 8 . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]

Author:  gowan [ Sat Mar 29, 2014 11:45 am ]
Post subject:  Re: Shimari invasion

There are dozens of variations possible after Whites invasion. This page on Sensei's Library shows a few of the more common variations:

http://senseis.xmp.net/?3453Enclosure43Invasion

How Black responds depends heavily on the larger context. For example Black might choose to let White live in the corner in exchange. In these shimari invasions it may not be possible to kill the White stones, or killing the white stone might allow White to get strong on the outside and erase a black moyo.

Author:  TIM82 [ Sat Mar 29, 2014 11:48 am ]
Post subject:  Re: Shimari invasion

What you want to do depends on positions around the corner - expecting to kill every single white stone in the area wont probably work, as :w1: is a valid probe. Note that you have two ataris available on move :b4: ...

See http://senseis.xmp.net/?3453Enclosure43Invasion

Author:  oca [ Mon Mar 31, 2014 3:20 am ]
Post subject:  Re: Shimari invasion

@EdLee : thanks, I now see that my :b8: was wrong.

Unfortunaltly, sente/gote is in my "I'm aware of but never use it" too long list, just before "ko fight" and "direction of play" :) I should definitly give sente more importance when choosing my next move.

@Everyone : Thanks a lot, I was aware that hoshi could be invaded, but with a shimari on komoku, I was thinking that :w1: was an overplay and that there should be a way to kill all the white invading stones...
I played komuku and shimari a lot wihtout even knowing that the invasion was possible...

As for the invasion of hoshi, I suppose we should not invade the shimari to early because of the wall the opponent will get in return. Is that right ?


I also looked at the page you pointed me to on SL :3453Enclosure43Invasion
and I didn't see any variation starting like that :

Click Here To Show Diagram Code
[go]$$W
$$ ----------------+
$$ . . . . . . ? ? |
$$ . . . . a . ? ? |
$$ . , . X 1 2 ? ? |
$$ . . . . b X ? ? |
$$ . . . , . . ? ? |
$$ . . . . . . . . |[/go]

So it should not be a good option for black...
I suppose that's because it will make black stones not to work well all together.
If I was white I would answer that :b2: with :w3: at (a) or (b)

Click Here To Show Diagram Code
[go]$$W white 3 at (a)
$$ ------------+
$$ . . . . . . |
$$ . . 3 . . . |
$$ . X 1 2 . . |
$$ . . 4 X . . |
$$ . , . . . . |
$$ . . . . . . |[/go]

To me, it's not that bad for black... so may be white would not do that...

Click Here To Show Diagram Code
[go]$$W white 3 at (b)
$$ ------------+
$$ . . . . . . |
$$ . . 4 . . . |
$$ . X 1 2 . . |
$$ . . 3 X . . |
$$ . , 5 6 . . |
$$ . . 7 . . . |
$$ . . . 8 . . |
$$ . . . . . . |[/go]

white should be happy to force black to crawl on the 3rd line in a region that black wanted for him (if not, why playing a shimari), I suppose that's why (or a least one of the reasons) :b2: is not a good choice...

Author:  HermanHiddema [ Mon Mar 31, 2014 3:42 am ]
Post subject:  Re: Shimari invasion

oca wrote:
@EdLee : thanks, I now see that my :b8: was wrong.

Unfortunaltly, sente/gote is in my "I'm aware of but never use it" too long list, just before "ko fight" and "direction of play" :) I should definitly give sente more importance when choosing my next move.

@Everyone : Thanks a lot, I was aware that hoshi could be invaded, but with a shimari on komoku, I was thinking that :w1: was an overplay and that there should be a way to kill all the white invading stones...
I played komuku and shimari a lot wihtout even knowing that the invasion was possible...

As for the invasion of hoshi, I suppose we should not invade the shimari to early because of the wall the opponent will get in return. Is that right ?


I also looked at the page you pointed me to on SL :3453Enclosure43Invasion
and I didn't see any variation starting like that :

Click Here To Show Diagram Code
[go]$$W
$$ ----------------+
$$ . . . . . . ? ? |
$$ . . . . a . ? ? |
$$ . , . X 1 2 ? ? |
$$ . . . . b X ? ? |
$$ . . . , . . ? ? |
$$ . . . . . . . . |[/go]

So it should not be a good option for black...
I suppose that's because it will make black stones not to work well all together.
If I was white I would answer that :b2: with :w3: at (a) or (b)



Neither a nor b would be the first move I would look at. This is my first instinct:

Click Here To Show Diagram Code
[go]$$W
$$ ----------------+
$$ . . . . . . . . |
$$ . . . 3 . . . . |
$$ . . . X 1 2 . . |
$$ . . . . . X . . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]


And then there are many variations. E.g:


Click Here To Show Diagram Code
[go]$$W Reasonable
$$ ----------------+
$$ . . . . 7 . . . |
$$ . 9 . 3 4 8 . . |
$$ . . 5 X 1 2 . . |
$$ . . . 6 . X . . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]



Click Here To Show Diagram Code
[go]$$W Reasonable
$$ ----------------+
$$ . . . . . . . . |
$$ . . . 3 4 . . . |
$$ . . 5 X 1 2 . . |
$$ . . . 7 6 X . . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]



Click Here To Show Diagram Code
[go]$$W Good for white
$$ ----------------+
$$ . . . . . . . . |
$$ . . . 3 . 5 6 . |
$$ . 7 . X 1 2 . . |
$$ . . . 4 . X . . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]



Click Here To Show Diagram Code
[go]$$W Disaster for black
$$ ----------------+
$$ . . . . . . . . |
$$ . . . 3 . . . . |
$$ . . 4 X 1 2 . . |
$$ . . . . 5 X . . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]


Click Here To Show Diagram Code
[go]$$W Different order
$$ ----------------+
$$ . . . . . . . . |
$$ . . . 3 6 . . . |
$$ . . 5 X 1 2 . . |
$$ . . . 7 4 X . . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]


Click Here To Show Diagram Code
[go]$$W May be playable if there is a white stone to the left of a
$$ ----------------+
$$ . . . . . . . . |
$$ . . 7 3 5 9 0 . |
$$ a 8 6 X 1 2 . . |
$$ . . . . 4 X . . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]


And in most of those diagrams, you could probably play elsewhere after :b4: (or even after :b2: ) and treat :w1: and :w3: as probing moves.

Author:  Bill Spight [ Mon Mar 31, 2014 8:37 am ]
Post subject:  Re: Shimari invasion

Click Here To Show Diagram Code
[go]$$W
$$ ----------------+
$$ . . . . . . . . |
$$ . . . . . . . . |
$$ . a b X 1 2 . . |
$$ . . . . , X . . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]


In Enclosure joseki Okubo Ichigen recommends "a" or "b" next.

Author:  oca [ Tue Apr 01, 2014 3:45 am ]
Post subject:  Re: Shimari invasion

Bill Spight wrote:
In Enclosure joseki Okubo Ichigen recommends "a" or "b" next.


Oh... ok, so :w1: is sacrifed then right ?

Author:  EdLee [ Tue Apr 01, 2014 8:41 am ]
Post subject: 

oca wrote:
Oh... ok, so :w1: is sacrifed then right ?
HermanHiddema wrote:
treat :w1: and :w3: as probing moves.

Author:  Bill Spight [ Tue Apr 01, 2014 9:12 am ]
Post subject:  Re: Shimari invasion

oca wrote:
Bill Spight wrote:
In Enclosure joseki Okubo Ichigen recommends "a" or "b" next.


Oh... ok, so :w1: is sacrifed then right ?


It certainly can be sacrificed, since :b2: is a passive response. :)

We say that it is treated lightly.

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