Life In 19x19

While studying some variations on 4-4 joseki I came upon one that I'm not following at the end. According the joseki dictionary I was looking the black 7 stone is necessary to live. I've played it a few times and am having troubles killing it as white if black tenukis instead of that last move. I'm sure the dictionary is more knowledgable than I am and I'm just not seeing the key move. Any thoughts on how white can kill if black skips that?

Push and when B block play Q18. I seem to recall variations where B does not die, but wishes he had because of the weak group created.

What DrStraw said. These are the common variations that I know:

should be the one space pincer at R-12.

s17 is a rather pathetic move. Please don't play it because some full-of-crap joseki source like Kogo's told you to.

There are many alternatives. Tenuki for one, an empty corner is probably bigger. Neither of white's groups is strong yet, so don't just think you are weak, white is weak too. He didn't extend on the right like he should, so pincer there like Bill said is much better spirit. Or jump out with your group at o15 or o14 which is nice and simple to get you out and strong and have miai of pincering either white group.

Black s18 in amatterof's variation is white's dream, black should jump out like o14. (Though obviously it's good to know that peep afterwards as the threat white carries if black does foolishly try to make eyespace in the corner now. If black really does need to live and doesn't mind strengthening an already strong white then he can 2nd line attach under white's pincer and then come back to s18).

Hi Nathan,

Adding to what's already discussed:

Nathanl wrote:According the joseki dictionary I was looking the black 7 stone is necessary to live.

This is only true if Black is already completely boxed in, and White is strong outside, so Black has no way to escape or fight back.
Then, if White takes S17, then Black is in big trouble.
So given all these constraints -- were they mentioned in your joseki dictionary ? -- (S17) makes life.

White's surroundings actually have to be very strong for s17 to be necessary to live, for example here black can scrape out a life. But sometimes you want to live before you need to because your opponent gets a lot of profit in sente from making you live small (here white s17 and the thickness from black doing 2nd line attach). However, if you got something equally (or more) nice with your tenuki for 2 then that's ok. White can also think about playing 5 at 6 which means black can't make eyes on the side so easily, but he breaks white's encircling shape and can run into the centre. Another idea is to play 1 at s17, which allows black to come out at o14 but that exchange is good for white for territory and unless black can break a white centre or get some nice counter attack on m17 he probably feels sad about running around on dame whilst white gets points whilst chasing, so that's why playing s17 himself could be a good idea.

Click Here To Show Diagram Code

[go]$$Wc 2 tenuki
$$ ----------------------+
$$ . . . . . . . . . . . |
$$ . . 5 4 6 . . . . 8 . |
$$ . . 7 O . X . . X 3 . |
$$ . , . . . . . X . O . |
$$ . . . . 1 . . . . . . |
$$ . . . . . . O . O . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . , . . . . . , . . . |[/go]

Bill Spight wrote: should be the one space pincer at R-12.

Hi Bill, is attaching at R13 also possible ? or would it be too aggressive ?

oca wrote: attaching ... aggressive

Think about that...

Interestingly, the position came up in one of the recent games in the AGA Pro Qualification Tournament. See move forward. As always, surroundings and the whole board matter...

There's some discussion of this move following the game posted here as well:

http://lifein19x19.com/forum/viewtopic. ... 51#p110551

snorri wrote:Interestingly, the position came up in one of the recent games in the AGA Pro Qualification Tournament. See move forward. As always, surroundings and the whole board matter...

Calling that the same position, even with the qualification, may confuse Nathanl.

As far as I know, getting a severe attack on black via the inside placement here normally *also* requires white to have a working ladder to the lower left.

Click Here To Show Diagram Code

[go]$$Wc Normal joseki shape with white approach, plus a push and block
$$ ----------------------+
$$ . . . . . . . . . . . |
$$ . . . . . . . T . B . |
$$ . . . W . X . . X W . |
$$ . , . . . . . X . O . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . O . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . O . . |
$$ . , . . . . . , . . . |[/go]

If instead the ladder favors black, followed by here is the key combination to survive. Black either kills white's attempt and has plenty of resources and strength afterwards, or trades and gets some of white's stones in return.

Click Here To Show Diagram Code

[go]$$Wc A and B are miai as long as the ladder is good for black
$$ ----------------------+
$$ . . . . . . . . . 4 . |
$$ . . . . . . 2 1 3 X . |
$$ . . . O . X b 5 X O . |
$$ . , . . . . 7 X 6 O . |
$$ . . . . . . . 8 . a . |
$$ . . . . . . . . O . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . O . . |
$$ . , . . . . . , . . . |[/go]

And here's the ladder:

Click Here To Show Diagram Code

[go]$$Wc Ladder
$$ ----------------------+
$$ . . . . . . . . . X . |
$$ . . . . . . X O O X . |
$$ . . . O . X 4 O X O . |
$$ . , . . . . O X X O . |
$$ . . . . . . 1 X 3 . . |
$$ . . . . . . . 2 O . . |
$$ . . . . . . . 5 . . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . O . . |
$$ . , . . . . . , . . . |[/go]

Moreover, in the event that black has managed beforehand to get white to respond submissively to a move such as the attachment like so, then black is actually okay here.

Click Here To Show Diagram Code

[go]$$Wc Black is quite hard to attack
$$ ----------------------+
$$ . . . . . . . . . . . |
$$ . . . . . . . . . X . |
$$ . . . O . X . . X O . |
$$ . , . . . . . X . O . |
$$ . . . . . . . . . . . |
$$ . . . . . . . B O . . |
$$ . . . . . . . . W . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . O . . |
$$ . , . . . . . , . . . |[/go]

doesn't work so well now because there isn't even a ladder. Black just wins outright.

Click Here To Show Diagram Code

[go]$$Wc
$$ ----------------------+
$$ . . . . . . . . . 4 . |
$$ . . . . . . 2 1 3 X . |
$$ . . . O . X . 5 X O . |
$$ . , . . . . 7 X 6 O . |
$$ . . . . . . 8 . . . . |
$$ . . . . . . . B O . . |
$$ . . . . . . . . W . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . O . . |
$$ . , . . . . . , . . . |[/go]

Click Here To Show Diagram Code

[go]$$Wc
$$ ----------------------+
$$ . . . . . . . 6 . X . |
$$ . . . . . 5 X O O X . |
$$ . . . O . X 3 O X O . |
$$ . , . . . 4 O X X O . |
$$ . . . . . . X 2 1 . . |
$$ . . . . . . . X O . . |
$$ . . . . . . . . O . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . O . . |
$$ . , . . . . . , . . . |[/go]

Obviously in a tactical mess like this, the fine placement of nearby stones could affect things a lot. But it does show that black has some resources here and that white's placement can often just fail to work.

I have added a sub variation, which I remember, to amatterof's SGF:



edit: Corrected a blunder in the SGF
edit^2: I have just seen that lightvector has already mentioned this variation, if an admin could remove this duplicate post, I'm ok with it!

Thanks! Great information. It's good to know it isn't as cut and dry as it was implied. I ended up playing it in a game as white to see how it went. Cut off the whole corner, although black could have defended better at several points.