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How do you defend against this invasion?

Posted: Tue Oct 16, 2012 12:56 am
by chef
Or is it no defendable?

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


My first instinct was the following
Click Here To Show Diagram Code
[go]$$B
$$ ------------
$$ | . . . . . .
$$ | . . . . . .
$$ | . . 6 . . 5
$$ | . 7 . 1 . .
$$ | . . 3 . . .
$$ | . . 2 4 . .[/go]


What are your thoughts?

Posted: Tue Oct 16, 2012 12:58 am
by EdLee
What are your variations after :b7:?

Re: How do you defend against this invasion?

Posted: Tue Oct 16, 2012 1:42 am
by Uberdude
chef wrote:Or is it no defendable?

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




This is a standard invasion, you can't expect to kill it cleanly. Black's usual responses are a-e below. The main strategic choice here is do you let white connect at a.

Click Here To Show Diagram Code
[go]$$B
$$ ------------
$$ | . . . . . .
$$ | . . . . . .
$$ | . . 6 b . 5
$$ | . d c 1 . .
$$ | . a 3 . . .
$$ | . e 2 4 . .[/go]

Black a cuts white, who will then try to live in the corner. It's not cleanly locally alive, but black has weaknesses which means it is usually impossible to kill, see some variations in http://senseis.xmp.net/?44PointLowAppro ... 33Invasion . If black can let white live in gote, and then attack the stones on the outside which are now weaker due to a taking away their eyespace then this is a good choice.

Black b lets white play at a (which black can answer at c or d), but keeps the corner territory. Playing this way is ok in yose, in middlegame it's usually a bit soft.

Black c also cuts white, and makes it harder to live in the corner, but doesn't hurt the outside stones so much. White can often tenuki and treat that exchange as kikashi.

Black d cuts and attacks the corner more severely than a, but has some shape weaknesses.

Black e (white blocks, then black plays b) enables black to prevent the connection at a in sente and then block the corner, but white can then capture at d in sente to make a strong ponnuki shape. This would be a bad choice if the 2 outside stones are weak, but if they are already strong it's ok.

Re: How do you defend against this invasion?

Posted: Tue Oct 16, 2012 3:33 am
by Phelan
chef wrote:Or is it no defendable?

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


What are your thoughts?

I'd go back and play 3 at 'a', or at :b5:.
I almost never like the kick exactly because of that possible invasion.

Also, nice to see you again, chef! :)

Re: How do you defend against this invasion?

Posted: Tue Oct 16, 2012 7:18 am
by skydyr
Generally, you don't want to kick and make white stronger unless you already have a stone in place to restrict white's eyespace, meaning that the two white stones on the outside should be relatively weak. At some point, depending on the situation, it may be handy to forestall the invasion by playing this way:

Click Here To Show Diagram Code
[go]$$B 3 Could be another standard connection as well
$$ ------------
$$ | . . . . . .
$$ | . . . . . .
$$ | . . . . . X
$$ | . . . X . .
$$ | 3 . X . . .
$$ | . 1 O O . .
$$ | . 2 . . . .[/go]


However, there needs to be a followup available, perhaps from the other side, to allow black to play this in sente, or it should be held in reserve until the endgame, when territory starts to matter. It's also important in the middlegame to make sure white stays weak after this if you haven't extracted the full benefit of attacking white's group as yet.

Re: How do you defend against this invasion?

Posted: Tue Oct 16, 2012 8:44 am
by Redundant
skydyr wrote:
Click Here To Show Diagram Code
[go]$$B 3 Could be another standard connection as well
$$ ------------
$$ | . . . . . .
$$ | . . . . . .
$$ | . . . . . X
$$ | . . . X . .
$$ | 3 . X . . .
$$ | . 1 O O . .
$$ | . 2 . . . .[/go]




:b3: here is objectively wrong. It should be a solid connection. :b3: leaves the peep aji which is both a ko threat and, depending on the outside conditions can help in an invasion of the corner.

Re: How do you defend against this invasion?

Posted: Tue Oct 16, 2012 9:06 am
by Solomon
Click Here To Show Diagram Code
[go]$$B
$$ ------------
$$ | . . . . . .
$$ | . . . . . .
$$ | . . 6 . . 5
$$ | . . a 1 . .
$$ | . . 3 . . .
$$ | . . 2 4 . .[/go]

It really, really depends on what you want and the global situation. I find myself playing 'a' most of the time though, not necessarily because it's the best response given the global situation but because I find most people fail miserably in handling :w6: after 'a'.

Image

Re: How do you defend against this invasion?

Posted: Wed Oct 17, 2012 12:04 pm
by chef
Thans guys. If defending this joseki is really obscure in which situation is it appropriate to use?

@phelan It's been a while hasn't it. It's nice to be back

Re: How do you defend against this invasion?

Posted: Wed Oct 17, 2012 2:19 pm
by Falcord
I like playing the empty triangle too, because... Well, it's one of the few good empty triangles you get to see!

Re: How do you defend against this invasion?

Posted: Wed Oct 17, 2012 6:11 pm
by jts
Araban: What counts as "miserable failure"?

Re: How do you defend against this invasion?

Posted: Wed Oct 17, 2012 6:53 pm
by Uberdude
jts wrote:What counts as "miserable failure"?


George W Bush (according to Google)

Re: How do you defend against this invasion?

Posted: Wed Oct 17, 2012 10:13 pm
by chef
From the replies I'm seeing, would it be fair to say that there isn't tried and true ways of defending the invasion?

Re: How do you defend against this invasion?

Posted: Wed Oct 17, 2012 10:18 pm
by Loons
I believe this can be regarded as submissive for black, but it is an option.
Click Here To Show Diagram Code
[go]$$Bm7
$$ ------------
$$ | . . . . . .
$$ | . . 7 . . .
$$ | . 5 O 1 . X
$$ | . 3 4 X . .
$$ | . 2 X 6 . .
$$ | . . O O . .[/go]

Re: How do you defend against this invasion?

Posted: Wed Oct 17, 2012 10:30 pm
by Bill Spight
chef wrote:From the replies I'm seeing, would it be fair to say that there isn't tried and true ways of defending the invasion?


It would be fair to say that there is no single tried and true way of responding to that invasion, there are a number of tried and true ways. :)

Re: How do you defend against this invasion?

Posted: Thu Oct 18, 2012 4:23 am
by Kirby
chef wrote:From the replies I'm seeing, would it be fair to say that there isn't tried and true ways of defending the invasion?


Another thing to consider, chef, is that black has chosen this path before getting to the final position mentioned in the original post.

By playing in this order, the position is left to give white some options (which black can reasonably respond to as mentioned by others). But black doesn't have to play this way.

For example, if there is an empty board on the left side, I often see a slightly different order in my games:
Click Here To Show Diagram Code
[go]$$W
$$ ------------
$$ | . . . . . .
$$ | . . . . . .
$$ | . . . . . B
$$ | . . . B . .
$$ | . . . . . .
$$ | . . 1 . . .[/go]


Note that the marked black stones have already been played earlier in the game.

I like "sente" - or at least feeling like I have sente. So in the past, I've "kicked" in attempt to get sente:

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


then I tenuki. This leaves white the option of invading at 3-3. Black can reasonably defend as others have stated, but white still gets the benefit of playing 3-3 if he wants.

This is because black chose this way of playing.

Alternatively, if black can play here in this situation:
Click Here To Show Diagram Code
[go]$$W
$$ ------------
$$ | . . . . . .
$$ | . . . . . .
$$ | . . . . . X
$$ | . 2 . X . .
$$ | . . . . . .
$$ | . . 1 . . .[/go]


This is more of a defensive move against the 3-3. Black has chosen a different route. It has pros and cons. I sometimes don't like this, because I feel it is so slow. White will probably get to play where he choses for the next move... But locally, maybe it defends the 3-3 better than kicking...

But this is all talking about a different order than you had. Let's talk about that order, but in the process, let's take a look at the bigger picture:

Click Here To Show Diagram Code
[go]$$B
$$ -------------
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . 1 . . .
$$ | . . . . . . .
$$ | . . 2 . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . , . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]


Above we have the same order given in the original post. As we've seen, black has many ways to respond to white from the position you provided... But some aspects make it seem like white got away with a lot by being able to invade with the 3-3, etc.

For that reason, for a board position as above, I feel that it is more common to play this way:
Click Here To Show Diagram Code
[go]$$B
$$ -------------
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . 3 .
$$ | . . . 1 . . .
$$ | . . . . . . .
$$ | . . 2 . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . , . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]


or this way:

Click Here To Show Diagram Code
[go]$$B
$$ -------------
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . 1 . . .
$$ | . . . . . . .
$$ | . . 2 . . . .
$$ | . . . . . . .
$$ | . . 3 . . . .
$$ | . . . . . . .
$$ | . . . , . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]


Or some other sort of pincer.

Let's take a look at the first one:
Click Here To Show Diagram Code
[go]$$B
$$ -------------
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . 3 .
$$ | . . . 1 . . .
$$ | . . a . . . .
$$ | . . 2 b . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . , . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]


Here, white can still obviously invade at the 3-3. That doesn't change. But there's a big difference. The exchange of black 'a' for white 'b' has not been made.

Why is that important? Well, as we've seen, even though black plays 'a', white still can invade the 3-3 when he wants. Black can get an "ok" result, but what are black's motives behind playing 'a', the kick? If he is trying to "protect" the 3-3, we've already seen that doesn't work. White can still invade. So it's better to omit this if you're trying to protect corner territory - a kick doesn't do the job.

That's why I don't think the kick is common in that kind of board position.

But it IS common in a position like the following:
Click Here To Show Diagram Code
[go]$$B
$$ -------------
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . 1 . . .
$$ | . . . . . . .
$$ | . . 2 . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . B . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]


Above, we can see that there is already a black stone on the left side. In this case, it's very common to play this way:
Click Here To Show Diagram Code
[go]$$B
$$ -------------
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . a .
$$ | . . . 1 . 5 .
$$ | . . 3 . . . .
$$ | . . 2 4 . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . B . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]


(or the last move at "a").

What's the difference? It's a difference in motives. As stated earlier, black cannot "defend" against the 3-3 this way. But his motive is different this time. Namely, since he has support on the left side, he can put pressure on attacking the white stones. In other words, the marked stones become something that white has to take care of, giving black more flexibility to achieve his own global goals:

Click Here To Show Diagram Code
[go]$$B
$$ -------------
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . X . X .
$$ | . . X . . . .
$$ | . . W W . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . X . . .
$$ | . . . . . . .
$$ | . . . . . . .[/go]


White is by no means going to die, necessarily. But black can utilize his stones in the corner, together with the stone on the left, to achieve a greater global goal.

It stands to note that in this case, if white does the 3-3, there is an attractive black response:

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


Why is black's response attractive? Because it puts even more pressure on the marked white stones. Yes, white might live in the 3-3. But black can get revenge on his attack against the marked, slightly heavy white stones.

And getting revenge is fun, isn't it? :twisted: