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 Post subject: Re: LZ help for position
Post #21 Posted: Sat Nov 03, 2018 6:50 am 
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Here's a question:

I run a virtual machine on the Google Cloud. I downloaded Lizzie, but it won't start though I've installed the latest Java. Any idea what could be the problem? Otherwise I try Sabaki because that is running, but takes more time to install Leela.


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 Post subject: Re: LZ help for position
Post #22 Posted: Thu Jan 10, 2019 9:52 am 
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What I find interesting is that LZ doesn't think at all that 'a' is a must-move, but in fact LZ tends to tenuki there while I see basically NO good players doing it.

Click Here To Show Diagram Code
[go]$$B
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . X . . X O . |
$$ | . . . X . . . . . , . . . . . X O O . |
$$ | . . . . . . . . . . . . . . . X X O . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]


Last edited by Pippen on Thu Jan 10, 2019 1:14 pm, edited 1 time in total.
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Post #23 Posted: Thu Jan 10, 2019 10:09 am 
Honinbo
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Hi Pippen,

Happy 2019. :)

I have no access to any bot except for DeepLeela.com on an ancient iphone5. :mrgreen:

DL: (a) 49.2%; (b) 49.6%
Another instance: (a) 50%; (b) 49.4%

Click Here To Show Diagram Code
[go]$$B (a)
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 3 . . |
$$ | . . . . . . . . . . . . . X . . X O . |
$$ | . . . X . . . . . , . . . . . X O O . |
$$ | . . . . . . . . . . . . . . . 1 X 2 . |
$$ | . . 8 9 . . . . . . . . . . . 4 O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 6 . . . . . . . . . . . . . . . |
$$ | . . O , . . 7 . . , . . . . . O . . . |
$$ | . . . . 5 . . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]
Click Here To Show Diagram Code
[go]$$B (b)
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 6 . . . |
$$ | . . . . . . . . . . . . . X . 4 X O . |
$$ | . . . X . . . . . , . . . . 5 X O O . |
$$ | . . . . . . . . . . . . . 0 . 2 X 1 . |
$$ | . . . . . . . . . . . . . . . 8 O 3 . |
$$ | . . . . . . . . . . . . . . . 9 7 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

I'm curious if you get similar results on your device(s) ? :)

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 Post subject: Re: LZ help for position
Post #24 Posted: Thu Jan 10, 2019 10:44 am 
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LZ157 doesn't consider "b", but once played, "a" and "b" seem roughly equal.

Attachment:
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a.JPG [ 90.22 KiB | Viewed 317 times ]


Attachment:
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b.JPG [ 91.37 KiB | Viewed 317 times ]


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b2.JPG [ 100.71 KiB | Viewed 317 times ]

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 Post subject: Re: LZ help for position
Post #25 Posted: Thu Jan 10, 2019 10:59 am 
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So basically it's a coin flip? Also: How good or bad are 42-43 for Black? With Leela 11 it would indicate a bad position for black.

@EdLee: My Leela 11 on my computer gets for 'a' = 50.99 and 'b' = 50.08 with like a 2h calculation, so it differs a little bit.

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 Post subject: Re: LZ help for position
Post #26 Posted: Thu Jan 10, 2019 1:12 pm 
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Lizzie reminds me of my mother. When i was little, she often would tell me what i should have done instead of what i did.

But if i ever asked "why should i have done that instead of this?", i only ever got the only answer that Lizzie gives:

"BECAUSE I SAY SO!!!!"


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 Post subject: Re: LZ help for position
Post #27 Posted: Thu Jan 10, 2019 1:53 pm 
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What I find interesting is that LZ doesn't think at all that 'a' is a must-move, but in fact LZ tends to tenuki there while I see basically NO good players doing it.

Click Here To Show Diagram Code
[go]$$B
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . X . . X O . |
$$ | . . . X . . . . . , . . . . . X O O . |
$$ | . . . . . . . . . . . . . . . X X O . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

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 Post subject: Re: LZ help for position
Post #28 Posted: Thu Jan 10, 2019 4:20 pm 
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Pippen wrote:
What I find interesting is that LZ doesn't think at all that 'a' is a must-move,..
'a' is yose - both black and white are strong and not surrounded with plenty of open space to live in, so neither of them needs 'a'.

the only reason you would want to play a gote yose move is that it's the biggest move on the board.

you could try comparing the positions after either side plays 'a' to figure out how big it is

and then compare the overall position after black 'a' with that of a different move somewhere else

maybe influence maps would help you see the big picture

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 Post subject: Re: LZ help for position
Post #29 Posted: Fri Jan 11, 2019 12:55 am 
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Pippen wrote:
How good or bad are 42-43 for Black? With Leela 11 it would indicate a bad position for black.


On an empty board, LZ157 thinks that Black's winrate is 46.4%, so 42% or 43% during the opening is slightly bad. According to her, the first mistake (about -2%) is :b5: at K3, she prefers to approach the lower left corner.

Pippen wrote:
What I find interesting is that LZ doesn't think at all that 'a' is a must-move, but in fact LZ tends to tenuki there while I see basically NO good players doing it.


That's because the lower left corner hasn't been approached yet. My impression is that LZ values approaching komokus, or making a shimari from a komoku, more than humans.

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 Post subject: Re: LZ help for position
Post #30 Posted: Fri Jan 11, 2019 3:27 am 
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Pippen wrote:
What I find interesting is that LZ doesn't think at all that 'a' is a must-move, but in fact LZ tends to tenuki there while I see basically NO good players doing it.

Click Here To Show Diagram Code
[go]$$Bc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . X . . X O . |
$$ | . . . X . . . . . , . . . . . X O O . |
$$ | . . . . . . . . . . . . . . . X X O . |
$$ | . . . . . . . . . . . . . . . b O . . |
$$ | . . . . . . . . . . . . . . . . c . . |
$$ | . . . . . . . . . . . . . . . . e . . |
$$ | . . . . . . . . . . . . . . . . d . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]


I see black playing tenuki, after first exchanging b for c, quite a lot recently in both AI and pro games (e.g. http://www.go4go.net/go/games/sgfview/81834). You can see the evolution of thinking in this joseki over the last few years:
- before AI s16 slide instead of r16 attach was common, AI made slide practically disappear (it's easy to tenuki and weak shape)
- old thinking for the attach joseki was after black extends at a (it's not just yose as jaca said: it is a base for both players) white group needs a base (if tenuki black pincer at r12 is powerful) so white extends to d or e.
- if white extended to d then sooner or latter black can exchange b for c. He might not want to do it too early because it loses some other aji (e.g. if pincer at r10 then s13 peep can be an aim), but it's more likely to be a black sente because white pushing there is quite easy to ignore for black and also makes white's extension too close and inefficient shape.
- (sometimes white would extend just one space to e, then she can answer push with hane, but it's a bit tight)
- so white pushes at b instead of an extension is a move bots liked and humans play a lot too now. The idea is to take that key sente point for black and attempt to build a bigger and more efficient right side. black can play a pincer on the right or peep s13 and then there can be complex fighting (taking the liberty makes q17 cut a useful resource for white to exploit) with weak groups for both but at least white isn't in an inefficient slack shape without black having to do anything.
- so now black says "hey! q14 is a good move for you isn't it, it's a good move for me too" and plays it instead of descending in the corner. This makes the most sense when black is developing the top side. Because the push extend exchange helps white make a base on the right side black descend in the corner is no longer as important: black will usually tenuki or continue pushing / knight move in the centre.

(jlt also made a good point about there being an unapproached 3-4 being available, that being bigger than 4-4 corners is a basic opening theory lesson from LZ)


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 Post subject: Re: LZ help for position
Post #31 Posted: Fri Jan 11, 2019 2:26 pm 
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Uberdude wrote:
it's not just yose.. it is a base for both players
call me slow-witted, but i have trouble following your argument. One reason is that i can't see the order of moves (i can't even remember now whose turn it is! i remember when writing my previous reply, i thought it was black's turn, but something you said made me think you think it's white's).

Another reason is that the text is far away from the diagram, making it impossible on my 24" computer screen to see the text and the diagram at the same time (it must be a nightmare to read on a smaller display). For a short text like Pippen's question that's not an issue because i can keep the whole question in mind when looking at the picture, but with a lengthy answer, the to-ing and fro-ing of having to scroll back and forth all the time between picture and commentary interferes with my comprehension.

So when i read the line about attach instead of slide, and saw a black stone on the point being talked about, i at first thought you were talking about black attaching instead of sliding - but sliding from what?? It took me a few moments and quite a bit of scrolling up and down to realise you were talking about white sliding, not black.

i suppose i could copy the picture and open it in another window next to the text (or open another browser window on the same url - but when i tried that, i found i could not narrow the second window to only contain the content of the reply; the gnome window manager insisted on showing me the uninteresting wide left margin all the time; i could only close in the right-hand side of the window - although that's not such a big deal as i can put the picture window on the left of the text window, but it does take up screen space which means the text has to be that much smaller).

Also the row letters are way over on the other side of the board, requiring me to look away from the stones to see which points the text is referring to.

[no! wait!! i mean put the picture on the right, and overlay the text window, as i don't have to scroll the picture but do have to scroll the text.. oh, but now the stones i want see are far away on the further side of the window, unless i overlay the text window half across the board window, but then i can't see the row lettering. sigh :scratch: ]

Is there a way to put a picture of just the 1/4 of the board being talked about and its text alongside each other, and to shift the row letters from the left to the right?

Aside from all that, whilst i can see that 'a' gives whichever side plays it a firmer base, don't both black and white already have enough stability to both be able to cope with whatever comes along? To the best of my memory, you said that if white tenukis, black can pincer. But that's true (ie pincer or kakari) for all white stones on the board, eg the one jlt mentioned, and all black ones too.

How can we know which stones are most vulnerable to a pincer? Which of them are most valuable?

i'm happy to listen to whatever pretty Lizzie has to tell me (or, rather, i would be if she were on my machine, which she isn't, yet..i may have to go up to the mountaintop to rob another bank to buy a bigger, faster, cooler machine just to see her moves of wisdom without burning its cpu), but as previously mentioned, she can only tell me what to do, not why to do it, so i'd still be left in the dark.

Reading what people are saying about GoAIs these days, it feels like there is a new God on the scene who moves in mysterious ways whom people are following with blind faith. i'm sure she knows miles better than me, but it would be so nice if she could explain what she's talking about. Mine not to reason why; mine but to follow in the footsteps of fashion leaders, and slide or attach my hemlines as Rumpole's "She Who Must be Obeyed" dictates.

Looking back at Pippen's original picture, the board looks like the stones of both sides are are maybe too heavily concentrated in just one corner of the board - there are already 10 of them in the top right, but just one in each of the other 3 corners. I suppose the bigger the investment, the more you have to protect it, but couldn't the players have hedged their bets with a more sabaki sequence?

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Post #32 Posted: Fri Jan 11, 2019 3:00 pm 
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Hi Pippen,

Freshly published just an hour ago :)

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 Post subject: Re: LZ help for position
Post #33 Posted: Fri Jan 11, 2019 3:58 pm 
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jaca wrote:
i'm happy to listen to whatever pretty Lizzie has to tell me (or, rather, i would be if she were on my machine, which she isn't, yet..i may have to go up to the mountaintop to rob another bank to buy a bigger, faster, cooler machine just to see her moves of wisdom without burning its cpu), but as previously mentioned, she can only tell me what to do, not why to do it, so i'd still be left in the dark.


I ran across a quote supposedly by Capablanca the other day, to the effect that the best way to learn chess openings and endgames was to study the games of the masters. Considering his own chess education, my guess is that he did not mean simply relying upon commentary. You can do a lot on your own. You can pick up a lot from observing, like children do, and you can also play around with positions and learn their characteristics.

Quote:
Looking back at Pippen's original picture, the board looks like the stones of both sides are are maybe too heavily concentrated in just one corner of the board - there are already 10 of them in the top right, but just one in each of the other 3 corners. I suppose the bigger the investment, the more you have to protect it, but couldn't the players have hedged their bets with a more sabaki sequence?


If stones are dumped randomly in one corner, usually there will be stones to attack and stones to protect, with some urgency. But if stones are played in one corner more or less intelligently, usually the more stones are played, the less urgent it is to play the next stone there. Even so, we can't just assume that the more stones that have been played in one place, the more likely that mistakes have been made. You do have to look at the sequence of play. :)

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Post #34 Posted: Fri Jan 11, 2019 4:14 pm 
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EdLee wrote:
Hi Pippen,

Freshly published just an hour ago :)


:clap: :tmbup:

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 Post subject: Re: LZ help for position
Post #35 Posted: Fri Jan 11, 2019 4:54 pm 
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Bill Spight wrote:
You can do a lot on your own. You can pick up a lot from observing, like children do, and you can also play around with positions and learn their characteristics.
Indeed so, that is indeed how children learn to imitate the language, and the mindsets, and the prejudices etc, of their parents and friends and newspapers. But personally, i feel like i learned 1,000,000 times more from Michael Redmond's commentaries than i ever learned from playing with myself, or would have learned from simply observing Lizzie crushing the man from Monte-Carlo. Its true that Lizzie did learn from playing with herself, but she had to play rather more games than i've had cups of tea in a whole lifetime - and quite possibly more than there is tea in China.

Bill Spight wrote:
usually the more stones are played, the less urgent it is to play the next stone there.
Doesn't it depend on how strong (and how valuable) those stones are? Wasn't that the point of Pippen's question? I thought they were strong, but i infer Uberdude is implying they aren't.

Please can someone ask Lizzie her opinion, and show us her expected follow-ups to 'a' or not 'a' for both sides (4 main lines in all)? it's starting to look to me like it's more complicated than i at first thought.

Bill Spight wrote:
You do have to look at the sequence of play. :)
i don't mean to quote you out of context - if you are referring to understanding how the game got to where it is, that's tautological - but in terms of what black should do next, surely how she got to where she is now is irrelevant?

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Post #36 Posted: Fri Jan 11, 2019 5:15 pm 
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jaca wrote:
Bill Spight wrote:
You do have to look at the sequence of play. :)
i don't mean to quote you out of context - if you are referring to understanding how the game got to where it is, that's tautological - but in terms of what black should do next, surely how she got to where she is now is irrelevant?


Except for ko and superko rules, the board has no memory. So yes, all the information you need to figure out the best play is right there on the board. But that does not mean that you understand the position. Knowing how it arose, understanding and evaluating the previous plays can help to understand and evaluate the current position. (It can also work the other way, so that understanding the current position can help understand the previous plays. :))

Edit: Let me try to give an example. Suppose that during a local fight you had connected some stones. Later on, you are not sure how to proceed, but one line of play would make that connection a bad play; if you choose that line, you should not have bothered to make it. Since you are not sure what to do, you should not choose that line of play. Even if it is the best line of play, to play it is to accept an inferior result. OC, if you know what to do, do it. But when you are unsure, play consistently. Have a little faith in yourself. :)

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Post #37 Posted: Fri Jan 11, 2019 5:43 pm 
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Bill Spight wrote:
Knowing how it arose, understanding and evaluating the previous plays can help to understand and evaluate the current position.
Perhaps it depends on one's style of thinking and way of remembering things - if you think mostly in terms of sequences, then you would mainly remember a position in terms of the sequence that led to it.

When MacBeth said "is this a dagger i see before me?!" the audience only knows what's going on because they know what happened beforehand. So in that kind of situation, history is most definitely not bunk.

But in a Go game, there is no ambiguity, no ellipsis, no allusions, no illusions (except in my case, as i often hallucinate about what is not there right in front of my eyes on the board! - seeing connections that aren't there, and not seeing ataris that are; i even didn't see the gorilla walking across the basketball court until i was told to look for it).

Bill Spight wrote:
(It can also work the other way, so that understanding the current position can help understand the previous plays. :))
Absolutely yes. That's exactly what Lizzie does, when she imagines a future current position, and backs up her opinion of it (in her case, the cold hard fact of the ultimate outcome) to evaluate the merits of alternatives on offer in her present current position.

So it works backwards, but not forwards...

And with that in mind, what are the probable futures of black 'a' or white 'a'? Uberdude has read out one line (if white tenukis, black can pincer), but there are still 2 other possible futures (making 3 in all, not 4):

black 'a'
black tenuki, white 'a'
black tenuki, white tenuki, black pincer

plus
black push, white push as in the NHK game
the push can't be called a tenuki

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Post #38 Posted: Mon Jan 14, 2019 2:55 am 
Judan

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jaca wrote:
Lizzie reminds me of my mother. When i was little, she often would tell me what i should have done instead of what i did.
But if i ever asked "why should i have done that instead of this?", i only ever got the only answer that Lizzie gives:
"BECAUSE I SAY SO!!!!"

Although Lizzie can't answer questions or give explanations in natural language, it does have unlimited patience in answering questions of the form "What are good moves in this position?", "What are some expected sequences of good play?", "Show me the good move/sequence to punish this move you said was bad" and "How good is this position?". This, coupled with some Go and analytic skill of the operator, does enable one to extract out reasons for why it says certain moves are good and bad. Here is an example: viewtopic.php?p=240352#p240352. Lizzie is a tool whose maximum benefit comes from using it interactively to answer your questions, not just looking at snapshots others have posted. Even on a weak computer LZ is so strong it can teach a lot (I recommend using the 15-block networks).


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Post #39 Posted: Mon Jan 14, 2019 6:50 am 
Judan

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Location: Cambridge, UK
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Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
jaca wrote:
Aside from all that, whilst i can see that 'a' gives whichever side plays it a firmer base, don't both black and white already have enough stability to both be able to cope with whatever comes along? To the best of my memory, you said that if white tenukis, black can pincer. But that's true (ie pincer or kakari) for all white stones on the board, eg the one jlt mentioned, and all black ones too.

How can we know which stones are most vulnerable to a pincer? Which of them are most valuable?


Stones which you don't want to or can't effectively sacrifice (aka heavy) are more vulnerable to a pincer . For example approach of 1 below to a 4-4 can be pincered, but that's usually not a worry for white because she can easily sacrifice it by jumping into the corner to get a perfectly decent local position. (If the global position means white doesn't want to do that there are other choices)
Click Here To Show Diagram Code
[go]$$W
$$ --------------------+
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . 5 3 . . |
$$ , . . . . 6 X 4 . . |
$$ . . . . . . . . . . |
$$ . . . . . . . 1 . . |
$$ . . . . . . . . . . |
$$ . . . . . . . 2 . . |
$$ . . . . . . . . . . |
$$ , . . . . . , . . . |[/go]


On the other hand with the position discussed in this thread white can't dodge to the corner to sacrifice the group, because the exchanges there have given black the corner and white some stones on the side. So if black descends at 1 and white tenukis then after pincer of 3 then white either saves the group (e.g. 4-8) and black is happy to profit whilst attacking, or white tenukis again and the whole lot is almost dead if black plays again (though he might build thickness at 4 instead).
Click Here To Show Diagram Code
[go]$$B
$$ --------------------+
$$ . . . . . . . . . . |
$$ . . . . . . . 1 . . |
$$ . . . . X . . X O . |
$$ , . . . . . X O O . |
$$ . . . . . . X X O . |
$$ . . . . 8 . 4 O 6 . |
$$ . . . . . . . . 5 . |
$$ . . . . . 7 . 3 . . |
$$ . . . . . . . . . . |
$$ , . . . . . , . . . |[/go]


Compare this to this position, after approach and answer white tenukid, then black 1 is a pincer, but white can again dodge into the corner (but with marked stone the corner life is more cramped than before). To avoid white having the choice of this dodge black will often kick the white approach stone (at 7) before pincering.
Click Here To Show Diagram Code
[go]$$B
$$ --------------------+
$$ . . . . . . . . . . |
$$ . . . . . 8 . . . . |
$$ . . . . B . . 2 6 . |
$$ , . . . . . X 3 4 . |
$$ . . . . . . . 7 5 . |
$$ . . . . . . . O . . |
$$ . . . . . . . . . . |
$$ . . . . . . . 1 . . |
$$ . . . . . . . . . . |
$$ , . . . . . , . . . |[/go]


And then this one, 5 is tenuki. By exchanging 3 for 4 white has lost the option to sacrifice 1 by jumping into the corner, so the pincer at 6 is more painful than above, white is heavier. For that reason if white slides at 3 she is committing to saving 1 so should probably finish making a base for the group with an extension to a or b. Having said that, slide and tenuki is not impossible as white can still try to make shape with c after the pincer, but that's quite an advanced idea for the dan levels and usually occurs if black's pincer is attackable too.
Click Here To Show Diagram Code
[go]$$W
$$ --------------------+
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . 2 . . 4 . . |
$$ , . . . . . X . 3 . |
$$ . . . . . . c . . . |
$$ . . . . . . . 1 . . |
$$ . . . . . . . . . . |
$$ . . . . . . b 6 . . |
$$ . . . . . . . a . . |
$$ , . . . . . , . . . |[/go]


This post by Uberdude was liked by: Bill Spight
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 Post subject: Re: LZ help for position
Post #40 Posted: Mon Jan 14, 2019 10:51 am 
Judan

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Uberdude wrote:
jaca wrote:
Aside from all that, whilst i can see that 'a' gives whichever side plays it a firmer base, don't both black and white already have enough stability to both be able to cope with whatever comes along? To the best of my memory, you said that if white tenukis, black can pincer. But that's true (ie pincer or kakari) for all white stones on the board, eg the one jlt mentioned, and all black ones too.

How can we know which stones are most vulnerable to a pincer? Which of them are most valuable?


Stones which you don't want to or can't effectively sacrifice (aka heavy) are more vulnerable to a pincer . For example approach of 1 below to a 4-4 can be pincered, but that's usually not a worry for white because she can easily sacrifice it by jumping into the corner to get a perfectly decent local position. (If the global position means white doesn't want to do that there are other choices)
Click Here To Show Diagram Code
[go]$$W
$$ --------------------+
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . 5 3 . . |
$$ , . . . . 6 X 4 . . |
$$ . . . . . . . . . . |
$$ . . . . . . . 1 . . |
$$ . . . . . . . . . . |
$$ . . . . . . . 2 . . |
$$ . . . . . . . . . . |
$$ , . . . . . , . . . |[/go]


On the other hand with the position discussed in this thread white can't dodge to the corner to sacrifice the group, because the exchanges there have given black the corner and white some stones on the side. So if black descends at 1 and white tenukis then after pincer of 3 then white either saves the group (e.g. 4-8) and black is happy to profit whilst attacking, or white tenukis again and the whole lot is almost dead if black plays again (though he might build thickness at 4 instead).
Click Here To Show Diagram Code
[go]$$B
$$ --------------------+
$$ . . . . . . . . . . |
$$ . . . . . . . 1 . . |
$$ . . . . X . . X O . |
$$ , . . . . . X O O . |
$$ . . . . . . X X O . |
$$ . . . . 8 . 4 O 6 . |
$$ . . . . . . . . 5 . |
$$ . . . . . 7 . 3 . . |
$$ . . . . . . . . . . |
$$ , . . . . . , . . . |[/go]


The last diagram put me in mind of the following game, a 5 stone game in which Black overvalued a pincered stone.

White was Honinbo Dosaku Meijin. Dosaku was so far ahead of his competition that he was said to have the strength of a 13 dan. In the ranking of the time, that meant that he could give an ordinary meijin 2-3 stones. Considering the advances in go skill over the last three centuries, Dosaku might be able to take White without komi against today's top players. :)


_________________
"Even in the Orient, children are often Occidental."

----------------------------------------------------

The Adkins Principle:

At some point, doesn't thinking have to go on?

— Winona Adkins


This post by Bill Spight was liked by: Uberdude
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