Click Here To Show Diagram Code

[go]$$Bc
$$ ------------------+
$$ . . . . . . . . . |
$$ . . . X O . . . . |
$$ . . . . X O O . . |
$$ . . . . . X X W . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]

Also played by 9p players and 2d bullies in your local go club this move is not joseki.

Feel free to discuss

Hi Gomoto,

Click Here To Show Diagram Code

[go]$$Bc ???
$$ ------------------+
$$ . . . . . . . . . |
$$ . . . X O . . . . |
$$ . . . . X O O . . |
$$ . . . . 1 X X W . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

Hi Bill, Locally, how's this result ?

Click Here To Show Diagram Code

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

vs.

Click Here To Show Diagram Code

[go]$$B
$$ ------------------+
$$ . . . . . . . . . |
$$ . . . X O . . X . |
$$ . . . . X O O X . |
$$ . . . . X X X O . |
$$ . . . . . . O . O |
$$ . . . . . . . O . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]

Let us have a look at some examples:

This is much to mild on black: (No worries Bill, I tried this first myself.)



This is much stronger:

I will be advocatus diaboli for this unmove:

Lee Sedol winning inspite of this "joseki"

Click Here To Show Diagram Code

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

Weon Seongjin, 9p - Lee Sedol, 9p, B+7.5 (Komi 6.5)
36th Korean KBS Cup, round 2, 2017-06-26

I did not find a game in my pro database yet, where ELF or LZ like the disputed move.

Probably the move is really not good on nearly all boards.
I challenge my fellow forum colleagues to find a board with a good evaluation of this move.

(I have to admit that on Waltheri a 50% winrate is shown for this joseki. But in my local pro database of the last years I get a different impression.)

Click Here To Show Diagram Code

[go]$$B
$$ ------------------+
$$ . . . . . . . . . |
$$ . . . X O . . . . |
$$ . . . . X O O . . |
$$ . . . . 1 X X O . |
$$ . . . . . . . 2 . |
$$ . . . . . . 3 . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]

Edit: But when this came up in pro play, tenukied.

I suggested the connection in order to avoid the (obsolete?) joseki. I. e.,

Click Here To Show Diagram Code

[go]$$Bc
$$ ------------------+
$$ . . . . . . . . . |
$$ . . . X O . . 7 . |
$$ . . . . X O O 5 . |
$$ . . . . 3 X X O . |
$$ . . . . . . 2 1 6 |
$$ . . . . . . . 4 . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]

If it is not good, then what does White have, but this?

Click Here To Show Diagram Code

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

The - exchange is plainly bad for White.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

My view on the joseki where black gets the corner and white a ponnuki on other side before Gomoto's post: locally it's good for black, but ok for white if the ponnuki is particularly good direction, e.g. destroying a black territory/moyo there. Seeing as white has the choice to play this hane or the more normal ponnuki white presumably doesn't go down this path unless that condition is true. Also you need to remember that if black has a stone on the 3rd line (not 4th) around the mid point of right side then instead of solid connection when you cut he can resist with atari on top because if you connect he can defend the other side as running the single stone out doesn't cause a collapse anymore. The dead corner stones have less aji than the other ponnuki joseki, but still a bit with the white attachment.

Checking the Lee Sedol game, I was intrigued to find Elf wanted to play the 3-3 invasion as the 3-4 attachment one to the right. This seems to make some sense: the right side of the corner is the more valuable one (b12 strong and left boring area, whereas k4 is somewhat attackable) so that's why Lee chose to take the ponnuki there, so if that's the case don't 3-3 but attach! Seems so simple when pointed out, this attachment instead of 3-3 to choose the direction is something the strong bots do a lot, I remember AlphaGo doing it in one of the WeiqiTv videos. Something relatively simple but profound we can learn from them (early 3-3 seems to have become a standard part of the go vocabulary for many pros now, but I've not seen many 3-4 attaches yet). But LeelaZero prefers the 3-3, taking the ponnuki on left and maybe letting it die later which I don't really get (unless the point is you are getting other big moves to let it die, and if they get other big moves then it lives).

Locally it's good for Black. Yes, but Black has played one more stone. So how much better?

Maybe it's a couple of points better than usual, which would be enough to queer it on an empty board, but not if conditions are right. But I have also noticed that no bots ever seemed to choose it as White. So maybe it's even better for Black than that.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

Challenge accepted and met! (admittedly my adjustment of Lee's game is rather artificial, the additional white stone on the left is to make that side even more boring and less desirable to take the ponnuki on the left, and the knight's move on right is to make the white 2 stones relatively weaker so taking ponnuki on right better; this exchange is clearly better for black as white's move is pretty crap whereas black's is sensible: Elf winrate went from black 49% to 69%, and black shouldn't 3-3 but 3-4 attach or knight press on right). Interestingly if black does hane and cut white initially wants to atari on top and then black takes left ponnuki, but after ~30k decides white should connect and black takes right ponnuki (this is because it takes a while to realise if white ataris on top black should NOT take the left ponnuki but connect on 2nd line making miai and very good for black). Black ends this sequence with 55% vs 52% for left ponnuki (and should play armpit hit instead of 4th line extension as Lee did).

When I say something is locally good I am including difference in number of stones in that judgement (which is from my trained neural networks plus some logical reasoning rather than any Jasiek-style evaluation). Otherwise you'd say a lone black 4-4 stone in a corner is good for black, I say it's even. One negative thing for white is the right ponnuki is rather weak if you don't add a move, more so than the left ponnuki (because if black plays the vital point there then white's push out takes an important liberty so actives the dead 2 stones in corner, not so here).

I did not mean to suggest anything different. That's why I did not quote you. But I should have made that clear. Sorry.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.