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 Post subject: How is your positional judgement? Game 20
Post #1 Posted: Sat Nov 09, 2019 5:23 am 
Honinbo

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Assuming area scoring with 7.5 pt. komi, after :b27: Elf estimates a winrate of 90% (49.1k playouts) for one player. Which player is it?

Click Here To Show Diagram Code
[go]$$Bc White to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . O X . . |
$$ | . . O , . X . O . , . O . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . O . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . X X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O O . . |
$$ | . . . . . . . . . . . . . . X . X X . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . . X . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Enjoy! :D

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 Post subject: Re: How is your positional judgement? Game 20
Post #2 Posted: Sat Nov 09, 2019 5:33 am 
Gosei
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Although Black's upper left is an old joseki not to the liking of AI's, on the right hand side, Black has such a good position that I can't see how White would have the upper hand overall. I'll take Black any time

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 Post subject: Re: How is your positional judgement? Game 20
Post #3 Posted: Sat Nov 09, 2019 6:03 am 
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Before Katago : I prefer white as it has more potential, and with the next move, he can probably nicely stabilize his stones on the right side to erase the potential on the right.

Katago : it agree with me (yay :rambo: ), and give white +11pts/77%wr

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 Post subject: Re: How is your positional judgement? Game 20
Post #4 Posted: Sat Nov 09, 2019 6:15 am 
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This one is not easy. Black is leading in terms of territory and has no weak groups. White has more influence, but has to take care of his weak group Q6, so I prefer Black.

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 Post subject: Re: How is your positional judgement? Game 20
Post #5 Posted: Sat Nov 09, 2019 6:25 am 
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Intuition says that black seems good.

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 Post subject: Re: How is your positional judgement? Game 20
Post #6 Posted: Sat Nov 09, 2019 7:36 am 
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First thoughts were that the bots wouldn't like Black's joseki choice in the top left, and the shape in the bottom right looks a little strange. Black has two stones on the second line and White has none.
But even if White were to turn the entire frameworks at the top and on the left into territory - which seems optimistic - it's hard to see how the count would be much more than even. Plus, there are two weak white stones in the bottom right. Presumably the next move will strengthen these, but one move won't even turn them into a secure group, so I'd expect Black to take more profit from the attack.
So, Black it is.

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 Post subject: Re: How is your positional judgement? Game 20
Post #7 Posted: Sat Nov 09, 2019 8:37 am 
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My first instinct is black : he has solid territory, some potential to develop and a weak group to attack. That said, white has a nice position on the left and the top isn't bad either if a bit open. And white has sente.

With sente white can play an extension on the right and black lose his attack target. Maybe he can bully that group a bit for some territory on the right but that's all. Then an invasion of the left looks big. There's a lot that can be done there. Whether to play first on the side or to attach against the shimari is a good question. Or maybe black should be satisfied with a reduction, getting sente to invade the top? The left seems bigger though, and with more potential of development.

Actually maybe the cap at E10, or the knight move at E9, followed by the B4 prope might be a good way to deal with the left.

Then I feel that black wouldn't have a bad game.

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 Post subject: Re: How is your positional judgement? Game 20
Post #8 Posted: Sat Nov 09, 2019 10:19 am 
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There are no glaring tactical inefficiencies, except maybe a little bit black's bottom right corner. Then for strategic efficiency, W's influence is coordinating well (especially if you can imagine moves getting played at G15 area), while B's influence is about to be nullified by a difficult-to-attack white group on the right. So, without much deep thought, I like white. Edited because I forgot to hide :oops:

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 Post subject: Re: How is your positional judgement? Game 20
Post #9 Posted: Sat Nov 09, 2019 3:23 pm 
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Interesting, this one I feel strongly that I should stay with my "at a glance" assessment and reading won't help (in contrast to that pesky game 19). At least, not for my reading ability :-)

White just feels bigger. Yes, black has a fair bit of solid territory, while white's frameworks are invadable, but white's stones look to me like a textbook example of efficiency. Apart from those two stranded on the right, which are too heavy to sacrifice. But it's white's move, and there's plenty of space around, so it shouldn't be too hard to settle those stones.

I do have trouble choosing the next move though:

Click Here To Show Diagram Code
[go]$$Wc19
$$---------------+
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . O X . . |
$$ . . . O X . . |
$$ . . . O X . . |
$$ . . . . X . . |
$$ . . O . . . . |
$$ . . X X . . . |
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . b . . . |
$$ . . . . . . . |
$$ . a . . . . . |
$$ . . . O O . . |
$$ . . X . X X . |
$$ . . . . . . . |
$$ . . . X . . . |
$$ . . . . . . . |
$$ . . . . . . . |
$$---------------+[/go]


'a' feels like the safe move, whereas 'b' does more damage to black's framework but is maybe too greedy. Which move I'd play would depend on my mood on the day (possibly on how afraid I am of my opponent!)

OK, now that I've tried thinking for myself, let's see what some bots think.
KataGo: on my machine, it agrees with what it told Tryss :-) W+11, 77% winrate. LZ-242 says 83%, and LZ-ELF says 91%. 20,000 playouts in each case. Nice to see a consensus amongst our expert advisors.

All three prefer 'a' as first choice move:

Click Here To Show Diagram Code
[go]$$Wc19
$$---------------+
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . O X . . |
$$ . . . O X . . |
$$ . . . O X . . |
$$ . . . . X . . |
$$ . . O . . . . |
$$ . . X X . . . |
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . b d . . |
$$ . . . . . . . |
$$ . a . . . . . |
$$ . . c O O . . |
$$ . . X . X X . |
$$ . . . . . . . |
$$ . . . X . . . |
$$ . . . . . . . |
$$ . . . . . . . |
$$---------------+[/go]


'b' doesn't rate a mention; 'c' is a close second choice (same evaluation as 'a' but less than a quarter of the playouts) and 'd' gets a cursory glance (same evaluation as 'a', only a few hundred playouts). When I put 'b' on the board, it's suboptimal but still good enough to win (2% winrate drop or 1 point loss according to KataGo, 3% drop for LZ-242, 5% drop for LZ-ELF).

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 Post subject: Re: How is your positional judgement? Game 20
Post #10 Posted: Sun Nov 10, 2019 4:55 pm 
Gosei
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Some variations of mine, after seeing my judgment was wrong, and one variation by LZ:


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 Post subject: Re: How is your positional judgement? Game 20
Post #11 Posted: Mon Nov 11, 2019 10:57 am 
Judan

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I think whole game tewari with my Elf hat on is a better judge than static positional judgement so here is a plausible sequence of play with my Elvish commentary.

Top right has the same weird "was it a shoulder hit to 3-3 and they blocked but then didn't hane" weird shape from game 12, in which Bill revealed it was the result of an initial 6-4 stone so let's say it was that. So Elf thinks 1 is quite bad (-12% before), 2-4 ok, 5 and 6 a little slow but equally so. 7 is good, bots like low approach to 3-4 (but probably closing top right more, maybe that corner actually happened before top left). 8 locally a bit bad (prefer to defend on left to prevent press) and globally more so as entering top left bigger, but then 9 is worse (press or tenuki better), 10 is ok. So black lost in this corner so far
Click Here To Show Diagram Code
[go]$$Bc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . 7 . . . . . . . . . . . . . . |
$$ | . . 2 , . 9 . 8 . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 0 . . . . . . . . . . . . 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . 4 , . . . . . , . . . . . , . . . |
$$ | . . . . 6 . . . . . . . . . . 3 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]


11 is definitely smaller than top right shimari, and locally probably slow this early in opening (but maybe it was later). 12 is too slow, and side move which bots don't like, 13 likewise, but probably a bit worse as white's side move does help defend against a weakness of group at top left (now that black slid to take corner) whereas black's is pure points. But now at least I have a white sente to go into the top right. In the last game both players made fair sized mistakes in this sequence, but the net effect can be simplified as the sticks of 3 stones are basically even but then black's r14 should be a hane not extend so let's say -10%+.
Click Here To Show Diagram Code
[go]$$Bcm11
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 1 . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . 4 5 . . |
$$ | . . O , . X . O . , . . . . . 6 7 . . |
$$ | . . . . . . . . . . . . . . . 8 9 . . |
$$ | . . . O . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . 0 . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 2 , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . . 3 . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]


20 for 21 is then a good exchange for white, event though black is building 4th line territory, 21 is just a points move as the 4 stones are already alive (white's follow up at r14 is gote, has cuts and black corner still happy), whereas 20 is important for strength of white's stones and avoiding too much shortage of libs pain. Would a pro really play 21 though rather than invade the top and attack the wall? 23 then slow? 24 a shoulder hit reduction a bot classic, 25 is a weird move we don't see bots play so presumably bad, 26 for 27 a nice little exchange because 25 didn't add libs to r5, and now white has sente and knight move at o7 to run away looks reasonable. So white leading.
Click Here To Show Diagram Code
[go]$$Wcm20
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . O X . . |
$$ | . . O , . X . O . , . 3 . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . O . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . 1 . . . . |
$$ | . . . . . . . . . . . . . . 4 2 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 5 7 . . |
$$ | . . . . . . . . . . . . . . 6 . X 8 . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . . X . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

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 Post subject: Re: How is your positional judgement? Game 20
Post #12 Posted: Mon Nov 11, 2019 11:39 am 
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It’d be an interesting stat to see how the actual game results correlated with Elf’s assessment, aggregated across all of these games.

These are all pro games, so I wonder how often the end result matched up such that Elf’s favored player won.

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 Post subject: Re: How is your positional judgement? Game 20
Post #13 Posted: Mon Nov 11, 2019 12:03 pm 
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In this case the player favored by Elf won the game. :)

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 Post subject: Re: How is your positional judgement? Game 20
Post #14 Posted: Mon Nov 11, 2019 12:06 pm 
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Bill Spight wrote:
In this case the player favored by Elf won the game. :)


Whoops - I guess I’m posting in the wrong thread (should’ve been the main one)..

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 Post subject: Re: How is your positional judgement? Game 20
Post #15 Posted: Mon Nov 11, 2019 2:03 pm 
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Kirby wrote:
Bill Spight wrote:
In this case the player favored by Elf won the game. :)


Whoops - I guess I’m posting in the wrong thread (should’ve been the main one)..


That's OK. Message received. :) I'll take care of it.

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 Post subject: Re: How is your positional judgement? Game 20
Post #16 Posted: Tue Nov 12, 2019 9:04 am 
Gosei
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Uberdude wrote:
I think whole game tewari with my Elf hat on is a better judge than static positional judgement so here is a plausible sequence of play with my Elvish commentary.


That is how I have understood, from John and Bill, how professionals think. I find it a very interesting perspective that historical evaluation would give better insight than static evaluation and I'm impressed you can do it so well.

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 Post subject: Re: How is your positional judgement? Game 20
Post #17 Posted: Tue Nov 12, 2019 11:44 am 
Judan

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Knotwilg wrote:
Uberdude wrote:
I think whole game tewari with my Elf hat on is a better judge than static positional judgement so here is a plausible sequence of play with my Elvish commentary.


That is how I have understood, from John and Bill, how professionals think. I find it a very interesting perspective that historical evaluation would give better insight than static evaluation and I'm impressed you can do it so well.


It works best with this kind of peaceful fuseki-style opening in which I can apply the bot-style opening principles I've absorbed over the last few years so have reasonable confidence in my ability to predict whether Elf thinks moves are good or bad. I'm much less able to do that on more dynamic fighting positions like game 19.

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 Post subject: Re: How is your positional judgement? Game 20
Post #18 Posted: Tue Nov 12, 2019 12:15 pm 
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Knotwilg wrote:
Uberdude wrote:
I think whole game tewari with my Elf hat on is a better judge than static positional judgement so here is a plausible sequence of play with my Elvish commentary.


That is how I have understood, from John and Bill, how professionals think. I find it a very interesting perspective that historical evaluation would give better insight than static evaluation and I'm impressed you can do it so well.


I don't know about other professionals, but Takemiya has said that he relies upon shape, overconcentration, etc., because with his style of play he cannot rely upon counting territory. At least, early in the game.

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 Post subject: Re: How is your positional judgement? Game 20
Post #19 Posted: Wed Nov 13, 2019 11:33 am 
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Kirby wrote:
It’d be an interesting stat to see how the actual game results correlated with Elf’s assessment, aggregated across all of these games.

These are all pro games, so I wonder how often the end result matched up such that Elf’s favored player won.


I have shown the actual game winner in my discussion of all games through Game 17, which is as far as I have caught up with my discussions. :)

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 Post subject: Re: How is your positional judgement? Game 20
Post #20 Posted: Sat Nov 23, 2019 2:25 am 
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Assuming area scoring with 7.5 pt. komi, after :b27: Elf estimates a winrate of 90% (49.1k playouts) for one player. Which player is it?

It's White. White won the game by resignation.

The game is GoGoD 1969-01-29a, a Honinbo League game between Takagawa Shusaku (W) vs. Fujisawa Hideyuki. Komi was 4½ pts.

Click Here To Show Diagram Code
[go]$$Bcm17 White is ahead
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . O X . . |
$$ | . . O , . X . O . , . O . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . O . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . X X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O O . . |
$$ | . . . . . . . . . . . . . . X . X X . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . . X . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Both players were considered to be masters of the opening. According to Elf neither player has blundered so far. How did White (Takagawa) get so far ahead? Fujisawa simply made more, and larger, detectable errors (greater than 4%) than he did. 9 of Black's first 14 moves were errors, only 2 of White's first 13 moves were.

I think that :b13: is a teachable moment. :)

Click Here To Show Diagram Code
[go]$$Bcm13 A textbook play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . X . . |
$$ | . . O , . X . O . , d . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . a . . . . . . X . . |
$$ | . . O , . c . . . , . . . . . , . . . |
$$ | . . . . O . b . . 1 . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


:b13: is a textbook play, and AFAIK, has appeared in some textbooks. According to the theory of the time, it was an ideal extension from the Black enclosure in the bottom right corner, threatening the jump to a or the checking extension to b. In addition it prevents White from making a double wing formation, a doubly ideal formation where White extends on both sides from the enclosure in the bottom left corner. :b13: was the obvious play for both Takagawa and Fujisawa.

Elf thinks that it loses 8½% to par. ;) It is not even on Elf's radar. What play does Elf recommend? The Go Seigen/AI shoulder blow at c? Perhaps in a different whole board position. That's actually Elf's fourth choice. In this position Elf's top choice is the pincer at d.

Click Here To Show Diagram Code
[go]$$Bcm13 Elf's main variation for :b13:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . 3 B . . |
$$ | . . O , . X . O . , 1 . . 4 . 2 . . . |
$$ | . . . . . . . . . . . . . . . 5 . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


After :b13: White plays the shoulder blow against :bc:. The continuation is joseki. As a student of Takagawa, I do not see the improvement for Black, but this just shows how much the bots devalue the sides.

Another teachable moment occurred a few moves later.

Click Here To Show Diagram Code
[go]$$Wcm14 The solid connection loses 11½%
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . 5 X . . |
$$ | . . O , . X . O . , . . . . . 1 2 . . |
$$ | . . . . . . . . . . . . . . . 3 6 . . |
$$ | . . . O . . . . . . . . . . . . 4 . . |
$$ | . . . . . . . . . . . . . . b . . a . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . . X . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


The natural looking solid connection, :b19:, loses 11½% to the AI kosumi at a. Once you see it, the kosumi looks like the obvious shape play, protecting against the push and cut, and exerting influence towards the side. It also prevents a push and cut if Black later plays the keima at b. A human blind spot. This was Fujisawa's largest mistake, BTW.

Elf's mainline after the kosumi

Click Here To Show Diagram Code
[go]$$Wcm20 Elf's mainline after :bc:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . X . . 6 4 2 7 1 . . . O X . . |
$$ | . . O , . X 8 O 5 3 . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . O . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . a . . B . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . 0 . 9 . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . . X . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


:w20: is the usual extension when the keima at a is threatened. Black invades at :b21: and takes territory with gote. Then White plays the shoulder blow at :w28:. Black attacks with the boshi at :b29:.

Click Here To Show Diagram Code
[go]$$Wcm20 Variation
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . X . 3 . . . . . . . . O X . . |
$$ | . . O , . X . O . , 1 . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . O . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . 2 . . B . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . 4 . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . . X . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


If White extends a bit further with :w20:, Black doees indeed reply with the keima, :b21:. Then if :w22: secures the top side, :b23: builds an impressive moyo.

A string of errors

Click Here To Show Diagram Code
[go]$$Bcm19 Five mistakes in a row
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . b . a . . . O X . . |
$$ | . . O , . X . O . , . 4 . . . O X . . |
$$ | . . . . . . . . . . . . . . . O 1 . . |
$$ | . . . O . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . 2 . . . . |
$$ | . . . . . . . . . . . . . . 5 3 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . . X . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


This game sequence shows both of Takagawa's errors, and three of Fujisawa's. We have already examined :b19:. :w20: is the double keima. The saying is, Don't let the double keima get away. Well, Elf thinks that it is a minor error, losing only 5½%. Elf prefers the third line extension at a, after which invades at b, with the same plan as above, after the kosumi.

:b21: seems normal, for Black to develop the right side moyo, but Elf thinks that it loses 9½%, making it Fujisawa's second largest error. Elf prefers to invade the top side, which is closer to becoming White territory. It seems to me that the bots prefer to make more compact moyos than the large scale moyos of the 20th century.

Elf's mainline for :b21:

Click Here To Show Diagram Code
[go]$$Bcm21 Pincer cum invasion
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . 9 7 8 . O X . . |
$$ | . . O , . X . W . , 1 . 4 . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . O . 5 . 2 . . 3 . . . . . X . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . 6 . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . . X . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


:b21: pincers the :wc: stone while also spoiling the chance for White to make a territorial moyo on the top side. Pushing through a small opening is usually strong, but if Black plays :b23: at 25, White will top the tree at 23. White manages to make some territory with :w24:, after which Black does push through with :b25:.

:w22: is Takagawa's second error, according to Elf. It loses only 4½%, which is right at the the borderline, I think. Here is Elf's mainline variation for :w22:

Click Here To Show Diagram Code
[go]$$Wcm22 More territorial play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . X . a . . 6 . 1 . . . O X . . |
$$ | . . O , . X . O . , . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . O . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . 2 . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 5 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 3 4 . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . . X . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


After :w22: makes territory, :b23: plays the double keima on the border of two moyos. Then White reduces the right side with :w24: and :w26:. :b27: invades the top side before White can play at a. Again note how Elf cares more about almost territory than about the large scale White moyo on the left side.

:b23: in the game looks good, as a move on the border of moyos. However, after White plays :w22: on the fourth line, Elf regards the top side as more urgent.

Elf's mainline for :b23:

Click Here To Show Diagram Code
[go]$$Bcm23 Invasion, running fight
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . 6 . . . . . . |
$$ | . . . . X . 2 . . . 5 3 4 . . O X . . |
$$ | . . O , . X . O . 1 . O . . . O X . . |
$$ | . . . . . . 0 8 7 . . . . . . O X . . |
$$ | . . . O . . . 9 . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . . X . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


:b23: invades the top side on the fourth line, after which both sides start to build a base on the third line. :b29: attacks the two White stones, leading to a running fight.

Click Here To Show Diagram Code
[go]$$Bcm33 Invasion, running fight, continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . O . . . . . . |
$$ | . . . . X . O . . . X X O . . O X . . |
$$ | . . O , . X . O . X . O . . . O X . . |
$$ | . . . 1 . . O O X . . . . . . O X . . |
$$ | . . 2 O 3 . 4 X 7 . . . . . . . X . . |
$$ | . . . . 5 . . 6 . . . . . . O . . . . |
$$ | . . . . . . 8 . . a . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . . X . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


:b33: - :b37: lean on White's left side, and White pushes out into the center. Elf stops here, probably because of a low number of playouts. It seems to me that Black may push into the center at a.

Back to the game

Click Here To Show Diagram Code
[go]$$Wcm24 Small error
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . O X . . |
$$ | . . O , . X . O . , . O . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . O . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . X X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 1 3 . . |
$$ | . . . . . . . . . . . . . . 2 . X 4 . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . . X . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Elf regards :b25: as a small error, losing 6% to simply replying at 26. Elf's mainline variation is of some interest. :)

Click Here To Show Diagram Code
[go]$$Bcm25 Simple response
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . O X . . |
$$ | . . O , . X . O . , . O . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . O . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . X X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . 8 . . 0 . O 1 . . |
$$ | . . . . . . . . . 7 6 . . . . . X . . |
$$ | . . O , . . . . . 5 4 . . . . 3 . . . |
$$ | . . . . O . . . . X . . . . 2 X . . . |
$$ | . . . . . . . . . . . 9 . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


:w26: is a standard tesuji is this corner situation. White follows with a normal shoulder blow at :w28:. Black pushes up a couple of times, then slides underneath with :b33:. :w34: starts to solidify the White group and creates some eye potential.

Finally, how does Elf see the near future of the game after :b27: ?

Click Here To Show Diagram Code
[go]$$Wcm28 Elf's continuation
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . X . 3 . . . . . . . . O X . . |
$$ | . . O , . X . O . , . O . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . O . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . X X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . 7 8 . . . |
$$ | . . . . . . . . . . . . . . . 2 . . . |
$$ | . . . . . . . . . . . . . 1 5 6 . . . |
$$ | . . . . . . . . . . . . . . 4 O O . . |
$$ | . . . . . . . . . . . . . . X . X X . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . . X . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


In the game Takagawa played :w28: at 35, but Elf prefers the keima by 7%. (A third small error by Takagawa.) After :b29: threatens the push and cut, White switches to the top side to secure some territory. Black, OC, pushes and cuts and secures a good bit of territory on the right side, while White gets some floating stones.

These last two diagrams illustrate a difficulty for me with bot recommendations, especially if the errors are small. In Elf's mainline Black's error secures a good bit of fourth line territory in exchange for a move on the top side and some floating stones, while the correct play allows White to make a nice group within Black's sphere of influence. It's almost as if you can tell the mistake because it leads to a better looking result. ;)

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

Everything with love. Stay safe.

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