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How to squash this bogus invasion?
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Author:  cdybeijing [ Wed Jul 21, 2010 12:39 am ]
Post subject:  How to squash this bogus invasion?
This came up in a recent handicap game of mine. I played S12 and denied black a base, but felt I should have done better. What's the strongest way of play here?

Is R10 a stronger move?
Author:  Li Kao [ Wed Jul 21, 2010 12:44 am ]
Post subject:  Re: How to squash this bogus invasion?
I think I would have played R12 as B. Threatening to cut and taking influence if it fails.
Author:  kirkmc [ Wed Jul 21, 2010 12:59 am ]
Post subject:  Re: How to squash this bogus invasion?
That's a move I play in certain circumstance, and which is played against me. I push the invader to live in feeble second-line life, as much as possible, and get super-thickness. When I invade there, it's only if the resulting thickness won't have a big effect (ie, if it's late enough in the game).
Author:  Harleqin [ Wed Jul 21, 2010 1:28 am ]
Post subject:  Re: How to squash this bogus invasion?
First of all, this is not "bogus". It would do you good not to ridicule your opponent's move, especially when you cannot find an answer that you consider satisfactory.

Second, what did you expect? In your sequence, Black secures the corner, White gets some shape, but is still unsettled, and Black has sente.

Yes, there are some other options, but none "squash" White.

The first that usually is considered is this, where Black closes off this group from the lower right side:

Click Here To Show Diagram Code
[go]$$Bc
$$ -----------------------
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . X . . . X . X . . . |
$$ . . . . . . . . X . . |
$$ . . . . . . . O O . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . 4 . . . |
$$ . . . . . . . . . 2 . |
$$ . . . . . . . X 1 O . |
$$ . . . . . . . . . 3 . |
$$ . . . . . . . . . . . |[/go]


If the white group gets settled later, there can still be the 3-3 invasion open.

Another variation might be this, where White is denied eye shape, but not closed off:

Click Here To Show Diagram Code
[go]$$Bc
$$ -----------------------
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . X . . . X . X . . . |
$$ . . . . . . . . X . . |
$$ . . . . . . . O O . . |
$$ . . . . . . . . . 4 . |
$$ . . . . . . . . 5 3 6 |
$$ . . . . . . . . 1 2 . |
$$ . . . . . . . X . O . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |[/go]


Anyway, what you played has its merits, too, so I would not be dissatisfied.
Author:  HermanHiddema [ Wed Jul 21, 2010 3:32 am ]
Post subject:  Re: How to squash this bogus invasion?
Harleqin wrote:

The first that usually is considered is this, where Black closes off this group from the lower right side:

Click Here To Show Diagram Code
[go]$$Bc
$$ -----------------------
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . X . . . X . X . . . |
$$ . . . . . . . . X . . |
$$ . . . . . . . O O . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . 4 . . . |
$$ . . . . . . . . . 2 . |
$$ . . . . . . . X 1 O . |
$$ . . . . . . . . . 3 . |
$$ . . . . . . . . . . . |[/go]


If the white group gets settled later, there can still be the 3-3 invasion open.


Harleqin analysis is correct, this :b1: is the normal move. I'd just thought I'd add that :w4: should normally be on the third line. Otherwise:


Click Here To Show Diagram Code
[go]$$Bc
$$ -----------------------
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . X . . . X . X . . . |
$$ . . . . . . . . X . . |
$$ . . . . . . . O O . . |
$$ . . . . . . . . . 7 . |
$$ . . . . . . . 4 6 . . |
$$ . . . . . . . . 5 2 . |
$$ . . . . . . . X 1 O . |
$$ . . . . . . . . a 3 . |
$$ . . . . . . . . . . . |[/go]


This crude push of :b5: becomes effective, and :b7: will remove White's base.


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


Like this, the cut at a becomes somewhat more serious due to the lost liberty, so it is not playable in all situations, but as long as the ladder is good, Black should have no trouble. And some of the aji of the 3-3 invasion is also diminished.
Author:  cdybeijing [ Wed Jul 21, 2010 6:07 am ]
Post subject:  Re: How to squash this bogus invasion?
Harleqin wrote:
First of all, this is not "bogus". It would do you good not to ridicule your opponent's move, especially when you cannot find an answer that you consider satisfactory.

Second, what did you expect? In your sequence, Black secures the corner, White gets some shape, but is still unsettled, and Black has sente.

Yes, there are some other options, but none "squash" White.

The first that usually is considered is this, where Black closes off this group from the lower right side:

Click Here To Show Diagram Code
[go]$$Bc
$$ -----------------------
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . X . . . X . X . . . |
$$ . . . . . . . . X . . |
$$ . . . . . . . O O . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . 4 . . . |
$$ . . . . . . . . . 2 . |
$$ . . . . . . . X 1 O . |
$$ . . . . . . . . . 3 . |
$$ . . . . . . . . . . . |[/go]


If the white group gets settled later, there can still be the 3-3 invasion open.

Another variation might be this, where White is denied eye shape, but not closed off:

Click Here To Show Diagram Code
[go]$$Bc
$$ -----------------------
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . X . . . X . X . . . |
$$ . . . . . . . . X . . |
$$ . . . . . . . O O . . |
$$ . . . . . . . . . 4 . |
$$ . . . . . . . . 5 3 6 |
$$ . . . . . . . . 1 2 . |
$$ . . . . . . . X . O . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |[/go]


Anyway, what you played has its merits, too, so I would not be dissatisfied.


I was not strictly speaking dissatisfied with the line I played. Being that it occured in a handicap game, I was playing to prevent white from forming a base, and succeeded in doing that.

The first line you show (noting Herman's correction) is what I was looking for in terms of getting a better result. Your diagram did not include the lower right hoshi stone that I had, and the value of that 3 high wall facing the hoshi, plus the fact that white is still not settled, would have given me the result I think is best.

With my line, white can get some compensation if he gets an opportunity to approach lower right and isolate my stone.
Author:  Alakazam [ Sun Jul 25, 2010 6:34 pm ]
Post subject:  Re: How to squash this bogus invasion?
Regarding the two diagrams above: The last diagram would never be played by white, he gets 0 points. I could be wrong, but I'd rather get cut than conenct on the first line and have like 0 points or eyes. White can be flexible and consider sacrificing if he were cut in the mess, especially since the 3-3 is open. In the first of the two diagrams above, third line looks more normal, yes, however if you push to the left of 2, as shown, white will not block, but extend o nthe second line I think, so the peep actually won't happen, and won't work if you change the order. If it happens, it will be in a situation where white is in danger and black can be hardcore.
Author:  Aphelion [ Fri Aug 06, 2010 10:36 am ]
Post subject:  Re: How to squash this bogus invasion?
In Guojuan's group classes said this was a common white handicap move which can be punished by the kosumi to push white down. Unfortunately I don't remember the sequence, but when I get the time I can try to dig up one of the lectures.

Edit: Harlequin's second diagram looks like one of the bad variations for white she showed. She also shows what happens if white allows the cut - this variation I don't remember.
Author:  Magicwand [ Fri Aug 06, 2010 10:42 am ]
Post subject:  Re: How to squash this bogus invasion?
Alakazam wrote:
Regarding the two diagrams above: The last diagram would never be played by white, he gets 0 points. I could be wrong, but I'd rather get cut than conenct on the first line and have like 0 points or eyes. White can be flexible and consider sacrificing if he were cut in the mess, especially since the 3-3 is open. In the first of the two diagrams above, third line looks more normal, yes, however if you push to the left of 2, as shown, white will not block, but extend o nthe second line I think, so the peep actually won't happen, and won't work if you change the order. If it happens, it will be in a situation where white is in danger and black can be hardcore.


you are absolutely correct. but if you play against skd or lower..it is one way to create black weak group.
i wouldn't play such varations against dan level but when you have to give many handycap...it is a useful tool to overcome taugh handycap. :)
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