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 Post subject: Re: KataGo @ Igo Hatsuyoron 120
Post #21 Posted: Sun Oct 27, 2019 10:38 am 
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Bill Spight wrote:
My guess is that they do not count liberties, but rely upon reading.

I’m not sure I buy this, because the bots are high dan with zero playouts. Doesn’t that mean liberty counting likely plays a role for both value and policy aspects of the bots?

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 Post subject: Re: KataGo @ Igo Hatsuyoron 120
Post #22 Posted: Sun Oct 27, 2019 11:16 am 
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wineandgolover wrote:
Bill Spight wrote:
My guess is that they do not count liberties, but rely upon reading.

I’m not sure I buy this, because the bots are high dan with zero playouts. Doesn’t that mean liberty counting likely plays a role for both value and policy aspects of the bots?


We know that some animals, who apparently do not count, are able to distinguish between five and six items at a glance. How many liberties top neural net bots are able to distingush, I don't know. But nakade liberties, which was the context of my remark, are another animal, as they require distinguishing under the stones liberties, and accounting for sente plays as well as gote fills. On top of which, we know that semeai are weak spots for today's bots. Counting liberties makes semeai much easier than not counting liberties.

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 Post subject: Re: KataGo @ Igo Hatsuyoron 120
Post #23 Posted: Sun Oct 27, 2019 11:42 am 
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lightvector wrote:
Bill, I think there would be no difference, the parity would come out the same way. :study:


Thanks, that was my guess. :)

Edit; But, since there is no captured stone in the mirror problem, won't the territory result also be Black +1? ;)

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 Post subject: Re: KataGo @ Igo Hatsuyoron 120
Post #24 Posted: Mon Oct 28, 2019 7:15 am 
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Cassandra wrote:
Click Here To Show Diagram Code
[go]$$Wcm94 W 94 (KataGo's Atari)
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . X . . . O X . |
$$ | . . . . . . . X O O . X O X O . . O . |
$$ | . . . . . X . O . . . X O . . O O . . |
$$ | . X O , . . . . . O . X . O O X . . . |
$$ | . . X X X X O O O . O X X . X X O O . |
$$ | . X . O O O X X X O . . X . X O . O . |
$$ | O O O O . X O O X X O O . O X . . X . |
$$ | O X . X . X . O O X O . . . X X X X X |
$$ | O X . X . . . O X X O . X X X X O O O |
$$ | X O O , . X . O X O O X X O O O O X . |
$$ | X X . O X . . O X O . X O O O . X X X |
$$ | X . . O X . . O X O . X O O X X X O O |
$$ | X X O 1 X . . O X O . X O O O X X X O |
$$ | X O O X O X . O X O . X X O O O X O O |
$$ | X O X . . X . O X O X . O X X X O O O |
$$ | O X X , X . . O X O O O O X O X O O X |
$$ | O . . . O X . O X X X X X ? O X X O X |
$$ | O . X . . . X O O O O O O X O X . O X |
$$ | . X . . . . . O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]


Sorry to disturb, but why would white not play at any of diagrams on this topic on O3, capture black dragon in the center, and therefore capture black's right seki group and even left big eye group?

This black's group is in atari during entire analysis, and eating it would finish game in instant.

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 Post subject: Re: KataGo @ Igo Hatsuyoron 120
Post #25 Posted: Mon Oct 28, 2019 7:25 am 
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Bojanic wrote:
This black's group is in atari during entire analysis, and eating it would finish game in instant.

Capturing the Hanezeki's Tail costs White about 24 points overall ;-)

The Hanezeki will be resolved (all of White's stone in the lower right corner will be captured), having the final effect that Black's big group in the upper right lives.

If White captured the Tail so early in the game, she would not have got the large amount of prisoners, which she otherwise gets during the successive reduction of the Nakade at the left edge.

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Igo Hatsuyoron #120 (still unresolved by professionals, maybe solved by four amateurs)

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 Post subject: Re: KataGo @ Igo Hatsuyoron 120
Post #26 Posted: Mon Oct 28, 2019 7:38 am 
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I see now, eating back 4 stones would create more liberties for W in lower right group.

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 Post subject: Re: KataGo @ Igo Hatsuyoron 120
Post #27 Posted: Mon Oct 28, 2019 7:48 am 
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What happens if at this, or some earlier stage, white starts to fill in black's liberties in upper right?
Click Here To Show Diagram Code
[go]$$Bc
$$ +---------------------------------------+
$$ | . . . . . X . O . . . . X . . . O X . |
$$ | . . . . X O O . O O . X O X O . . O . |
$$ | . . . X X X X O . . . X O . . O O . . |
$$ | . X O , X O O . . O . X . O O X . . . |
$$ | . . X X X X O O O . O X X . X X O O . |
$$ | . X . O O O X X X O . . X . X O . O . |
$$ | O O O O . X O O X X O O O O X . . X . |
$$ | O X . X . X . O O X O . . . X X X X X |
$$ | O X . X . X . O X X O . X X X X O O O |
$$ | X O O X . X O O X O O X X O O O O X . |
$$ | X X O O X . . O X O . X O O O . X X X |
$$ | X X . O X . . O X O . X O O X X X O O |
$$ | X X O P X . . O X O . X O O O X X X O |
$$ | X O O X . X . O X O . X X O O O X O O |
$$ | X O X . X X . O X O X . O X X X O O O |
$$ | O X X , X X . O X O O O O X O X O O X |
$$ | O . . . O X O O X X X X X . O X X O X |
$$ | O . X . X O . O O O O O O X O X . O X |
$$ | . X . . X O O O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]


Black has some 17 liberties, it is difficult to count how many white has on the left.

But the idea is, if white eats big black group in center, it will take him 6 moves for black to eat seki group and liberate his upper right group.

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 Post subject: Re: KataGo @ Igo Hatsuyoron 120
Post #28 Posted: Mon Oct 28, 2019 7:53 am 
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Bojanic wrote:
What happens if at this, or some earlier stage, white starts to fill in black's liberties in upper right?

Black occupies the same number of liberties of White's group at the left edge.

We call this sequence of these exchanges of liberties "The Main Semeai".

It can be played before the remaining "usual" endgame (because these moves do not affect the Main Semeai), or after, as we have choosen in our presentation, following a recommendation of Prof. Jeong from Korea (just because the outcome of the Main Semeai is already decided).

+ + + + +

You might want to visit our website (see my signature below). Nearly every question you might have is already answered there.

But, as a matter of course, I will still answer your questions here.

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 Post subject: Re: KataGo @ Igo Hatsuyoron 120
Post #29 Posted: Mon Oct 28, 2019 8:03 am 
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Cassandra wrote:
Black occupies the same number of liberties of White's group at the left edge.

If it is the same number of liberties, white would win semeai.
When they come to five liberties each, white can eat center group, and capture black's group.

Do you have variation with start of liberty filling?

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 Post subject: Re: KataGo @ Igo Hatsuyoron 120
Post #30 Posted: Mon Oct 28, 2019 8:18 am 
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Cassandra wrote:
You might want to visit our website (see my signature below). Nearly every question you might have is already answered there.

But, as a matter of course, I will still answer your questions here.


Found it on your site, it is a bit difficult to navigate.
http://igohatsuyoron120.de/2015/0503.htm#q180v

Black has two more liberties, so he can connect tail when white reaches 5 liberties.

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 Post subject: Re: KataGo @ Igo Hatsuyoron 120
Post #31 Posted: Mon Oct 28, 2019 8:38 am 
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Bojanic wrote:
Found it on your site, it is a bit difficult to navigate.

Sorry, but the problem is so overwhelming complex.

And my knowledge of website design was not sufficient to do have more than static html.

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Igo Hatsuyoron #120 (still unresolved by professionals, maybe solved by four amateurs)

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 Post subject: Re: KataGo @ Igo Hatsuyoron 120
Post #32 Posted: Sat Dec 07, 2019 6:54 pm 
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There was an update on this posted yesterday, very fascinating read! https://blog.janestreet.com/deep-learni ... the-world/

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This post by sorin was liked by 2 people: Bill Spight, Gomoto
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 Post subject: Re: KataGo @ Igo Hatsuyoron 120
Post #33 Posted: Sat Dec 07, 2019 8:15 pm 
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Can not go to sleep

My precious ...

Exploring two space high pincer of the 3-4 low approach with the new Kata-Igo network

This looks very exciting

Fascinationg to watch the new opinions on the variations

First there was a digital Go Seigen offering to teach me. Now it feels like the entire Honinbo lineup is visiting and discussing the variations in front of me

I am so grateful

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 Post subject: Re: KataGo @ Igo Hatsuyoron 120
Post #34 Posted: Mon Dec 09, 2019 2:51 pm 
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Flying below the radar of area scoring

Lightvector highlighted (and simultaneously warned us all?) that KataGo – using area scoring – will be unable to distinguish between W+1(territory scoring) and W+2(territory scoring). This posting will show how significant his annotation was.

Click Here To Show Diagram Code
[go]$$Wcm120
$$ +---------------------------------------+
$$ | . . . X O . . . . . . . X X . . O X . |
$$ | . . . X X O O X O O . X O X O . . O . |
$$ | . . . X O X O O . . . X O O . O O . . |
$$ | . X O , . X X 2 3 O . X . O O X . . . |
$$ | . . X X X X O O O . O X X . X X O O . |
$$ | . X . O O O X X X O . . X . X O O . . |
$$ | O O O O 1 X O O X X O O 6 O X . . X . |
$$ | O X . X . X . O O X O . . . X X X X X |
$$ | O X . X . . . O X X O . X X X X O O O |
$$ | X O O X . X . O X O O X X O O O O X . |
$$ | X X O O X . . O X O . X O O O . X X X |
$$ | X X . O X . . O X O . X O O X X X O O |
$$ | X X O O X . . O X O . X O O O X X X O |
$$ | X O O 5 O X . O X O . X X O O O X O O |
$$ | X O X O 4 X . O X O X . O X X X O O O |
$$ | O X X X X X . O X O O O O X O X O O X |
$$ | O . . . O X O O X X X X X . O X X O X |
$$ | O . X . X O . O O O O O O X O X . O X |
$$ | . X . . X O O O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]

White's bad-shape move at 120 is gote locally, so Black – after inserting some forcing moves – might play tenuki with 125.

Click Here To Show Diagram Code
[go]$$Wcm126
$$ +---------------------------------------+
$$ | . . . X O . . . . . . . X X . . O X . |
$$ | . . . X X O O X O O . X O X O . . O . |
$$ | . . . X O X O O . . . X O O . O O . . |
$$ | . X O , . X X X O O . X . O O X . . . |
$$ | . . X X X X O O O . O X X . X X O O . |
$$ | . X . O O O X X X O . . X . X O O . . |
$$ | O O O O O X O O X X O O X O X . . X . |
$$ | O X . X . X . O O X O . . . X X X X X |
$$ | O X . X 4 1 2 O X X O . X X X X O O O |
$$ | X O O X . X 3 O X O O X X O O O O X . |
$$ | X X O O X . . O X O . X O O O . X X X |
$$ | X X . O X . . O X O . X O O X X X O O |
$$ | X X O O X . . O X O . X O O O X X X O |
$$ | X O O O O X . O X O . X X O O O X O O |
$$ | X O X O X X . O X O X . O X X X O O O |
$$ | O X X X X X . O X O O O O X O X O O X |
$$ | O . . . O X O O X X X X X . O X X O X |
$$ | O . X . X O . O O O O O O X O X . O X |
$$ | . X . . X O O O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]

If Black plays away, White's wedge at 126 is best.

Click Here To Show Diagram Code
[go]$$Wcm130
$$ +---------------------------------------+
$$ | . . . X O . . . . . . . X X . . O X . |
$$ | . . . X X O O X O O . X O X O . . O . |
$$ | . . . X O X O O . . . X O O . O O . . |
$$ | . X O , . X X X O O . X . O O X . . . |
$$ | . . X X X X O O O . O X X . X X O O . |
$$ | . X . O O O X X X O . . X . X O O . . |
$$ | O O O O O X O O X X O O X O X . . X . |
$$ | O X . X a X 1 O O X O . . . X X X X X |
$$ | O X . X X 2 X O X X O . X X X X O O O |
$$ | X O O X b X O O X O O X X O O O O X . |
$$ | X X O O X 5 . O X O . X O O O . X X X |
$$ | X X . O X 3 . O X O . X O O X X X O O |
$$ | X X O O X 4 . O X O . X O O O X X X O |
$$ | X O O O O X . O X O . X X O O O X O O |
$$ | X O X O X X . O X O X . O X X X O O O |
$$ | O X X X X X . O X O O O O X O X O O X |
$$ | O . . . O X O O X X X X X . O X X O X |
$$ | O 6 X . X O . O O O O O O X O X . O X |
$$ | . X . . X O O O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]

White did not only destroy all of Black's territory in the left centre.
She also keeps her liberty at a, and created an additional approach-move liberty at b.

Click Here To Show Diagram Code
[go]$$Wcm136
$$ +---------------------------------------+
$$ | . . . X O 1 . . . . . 6 X X 5 . O X . |
$$ | . . . X X O O X O O . X O X O . . O . |
$$ | . . . X O X O O . . . X O O . O O . . |
$$ | . X O , . X X X O O . X . O O X . . . |
$$ | . . X X X X O O O . O X X . X X O O . |
$$ | . X . O O O X X X O . . X . X O O . . |
$$ | O O O O O X O O X X O O X O X . . X . |
$$ | O X . X . X O O O X O . 7 . X X X X X |
$$ | O X . X X X X O X X O . X X X X O O O |
$$ | X O O X . X O O X O O X X O O O O X . |
$$ | X X O O X O 3 O X O . X O O O . X X X |
$$ | X X . O X O 2 O X O . X O O X X X O O |
$$ | X X O O X X 4 O X O . X O O O X X X O |
$$ | X O O O O X . O X O . X X O O O X O O |
$$ | X O X O X X . O X O X . O X X X O O O |
$$ | O X X X X X . O X O O O O X O X O O X |
$$ | O . . . O X O O X X X X X . O X X O X |
$$ | O X X . X O . O O O O O O X O X . O X |
$$ | . X . . X O O O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]

White 136 and Black 137 are miai.
Finally, White answers at the top right, wedging in at 142.

Click Here To Show Diagram Code
[go]$$Bcm143
$$ +---------------------------------------+
$$ | . . . X O O . . . . . X X X O . O X . |
$$ | . . . X X O O X O O . X O X O . . O . |
$$ | . . . X O X O O . . . X O O . O O . . |
$$ | . X O , . X X X O O . X . O O X . . . |
$$ | . . X X X X O O O . O X X 2 X X O O . |
$$ | . X . O O O X X X O . . X 3 X O O . . |
$$ | O O O O O X O O X X O O X O X . . X . |
$$ | O X . X . X O O O X O . O 1 X X X X X |
$$ | O X . X X X X O X X O . X X X X O O O |
$$ | X O O X . X O O X O O X X O O O O X . |
$$ | X X O O X O O O X O . X O O O . X X X |
$$ | X X . O X O X O X O . X O O X X X O O |
$$ | X X O O X X X O X O . X O O O X X X O |
$$ | X O O O O X . O X O . X X O O O X O O |
$$ | X O X O X X . O X O X . O X X X O O O |
$$ | O X X X X X . O X O O O O X O X O O X |
$$ | O . . . O X O O X X X X X . O X X O X |
$$ | O X X . X O . O O O O O O X O X . O X |
$$ | . X . . X O O O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]

Black 143 might be the reply that comes to mind first, but the subsequent sequence will not change the final score.

Click Here To Show Diagram Code
[go]$$Wcm146
$$ +---------------------------------------+
$$ | . . . X O O . . . . . X X X O . O X . |
$$ | . . . X X O O X O O . X O X O . . O . |
$$ | . . . X O X O O . . 1 X O O . O O . . |
$$ | . X O , . X X X O O . X . O O X . . . |
$$ | . . X X X X O O O . O X X O X X O O . |
$$ | . X . O O O X X X O . . X X X O O . . |
$$ | O O O O O X O O X X O O X . X . . X . |
$$ | O X . X . X O O O X O 2 O X X X X X X |
$$ | O X . X X X X O X X O . X X X X O O O |
$$ | X O O X . X O O X O O X X O O O O X . |
$$ | X X O O X O O O X O . X O O O . X X X |
$$ | X X . O X O X O X O . X O O X X X O O |
$$ | X X O O X X X O X O . X O O O X X X O |
$$ | X O O O O X . O X O . X X O O O X O O |
$$ | X O X O X X . O X O X . O X X X O O O |
$$ | O X X X X X . O X O O O O X O X O O X |
$$ | O . . . O X O O X X X X X . O X X O X |
$$ | O X X . X O . O O O O O O X O X . O X |
$$ | . X . . X O O O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]

Black 147 is sente, ...

Click Here To Show Diagram Code
[go]$$Wcm148
$$ +---------------------------------------+
$$ | . . . X O O . . . . . X X X O . O X . |
$$ | . . . X X O O X O O . X O X O . . O . |
$$ | . . . X O X O O . . O X O O . O O . . |
$$ | . X O , . X X X O O . X . O O X . . . |
$$ | . . X X X X O O O . O X X O X X O O . |
$$ | 2 X . O O O X X X O . . X X X O O . . |
$$ | O O O O O X O O X X O O X . X . . X . |
$$ | O X . X . X O O O X O X . X X X X X X |
$$ | O X . X X X X O X X O 1 X X X X O O O |
$$ | X O O X . X O O X O O X X O O O O X . |
$$ | X X O O X O O O X O . X O O O . X X X |
$$ | X X . O X O X O X O . X O O X X X O O |
$$ | X X O O X X X O X O . X O O O X X X O |
$$ | X O O O O X . O X O . X X O O O X O O |
$$ | X O X O X X . O X O X . O X X X O O O |
$$ | O X X X X X . O X O O O O X O X O O X |
$$ | O . . . O X O O X X X X X . O X X O X |
$$ | O X X . X O . O O O O O O X O X . O X |
$$ | . X . . X O O O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]

...but White will capture this stone (and connect) in the very end.
Black 149 continues with the Main Semeai.

The game will still end with W + 2.

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

Click Here To Show Diagram Code
[go]$$Bcm143
$$ +---------------------------------------+
$$ | . . . X O O . . . . . X X X O . O X . |
$$ | . . . X X O O X O O . X O X O . . O . |
$$ | . . . X O X O O . . . X O O . O O . . |
$$ | . X O , . X X X O O . X . O O X . . . |
$$ | . . X X X X O O O . O X X a X X O O . |
$$ | . X . O O O X X X O . . X 1 X O O . . |
$$ | O O O O O X O O X X O O X O X . . X . |
$$ | O X . X . X O O O X O b Q c X X X X X |
$$ | O X . X X X X O X X O . X X X X O O O |
$$ | X O O X . X O O X O O X X O O O O X . |
$$ | X X O O X O O O X O . X O O O . X X X |
$$ | X X . O X O X O X O . X O O X X X O O |
$$ | X X O O X X X O X O . X O O O X X X O |
$$ | X O O O O X . O X O . X X O O O X O O |
$$ | X O X O X X . O X O X . O X X X O O O |
$$ | O X X X X X . O X O O O O X O X O O X |
$$ | O . . . O X O O X X X X X . O X X O X |
$$ | O X X . X O . O O O O O O X O X . O X |
$$ | . X . . X O O O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]

However, Joachim suggested answering White's wedge (triangled) by giving atari from above, with the move at 143 here.

In principle, this move is a kind of Michael Redmond's kikashi, just played on the other side of the bamboo joint. Black gains an additional liberty at a, being worth one destroyed point of White territory.
(Funnily enough I had to convince Joachim from the validity of the above mentioned effect in this case. Usually, it is Joachim, who has to remind ME of findings that we had a decade ago.)

Black will capture at c, only after White connected at b.

+ + + + +

Let's compare the final board positions:

Click Here To Show Diagram Code
[go]$$B
$$ --------------------------------------------------------------------------------+
$$ - . . . X O O a . . . O X X X O . O X . - . . . X O O P . . . O X X X O . O X . -
$$ - . . . X X O O X O O O X O X O . . O . - . . . X X O O X O O O X O X O . . O . -
$$ - . . . X O X O O . b O X O O O O O . . - . . . X O X O O . P X X O O O O O . . -
$$ - . X O , . X X X O O O X . O O X O . . - . X O , . X X X O O . X . O O X O . . -
$$ - . . X X X X O O O . O X X . X X O O . - . . X X X X O O O . O X X O X X O O . -
$$ - X X X O O O . . . O . O X X X O O O O - X X X O O O . . . O . O X X X O O O O -
$$ - O O O O O X O O . . O O X c X O O X O - O O O O O X O O . . O O O Q X . . X O -
$$ - O X X X X X O O O . O P O X X X X X X - O X X X O X . O O . O e O . X X X X X -
$$ - O X X X X B X O . . O O X X X X . . . - O X X X X Y . O . . O O X X X X . . . -
$$ - O O O X Z X O O . O O X X . . , . X X - O O O X f X . O . O O X X . . , . X X -
$$ - . O O O X O O O . O O X . . . X X X X - X X O O X . O O . O . X . . . X X X X -
$$ - X X O O X O X O . O . X . . X X X . . - X X O O X X . O . O O X . . X X X . . -
$$ - X X O O X X X O . O . X . . . X X X . - . O O O X X . O . O O X . . . X X X . -
$$ - O O O O O X . O . O X X X . . . X . . - O O O O O X . O . O X X X . . . X . . -
$$ - O O X O X X . O . O X O O X X X . . . - O O X O X X . O . O X O O X X X . . . -
$$ - O X X X X X . O . O O O O X O X . . X - O X X X X X . O . O O O O X . X . . X -
$$ - O X . . O X O O . . . O O O O X X . X - O X . . O X O O . . . O O O O X X . X -
$$ - O X X . X O . O O O O O O X . X X . X - O X X . X O . O O O O O O X . X X . X -
$$ - X X . . X O O O . . . . O X X X X . . - X X . . X O O O . . . . O X X X X . . -
$$ --------------------------------------------------------------------------------+[/go]

In Joachim's variation (at the left), White has two points of territory at the top, at a and at b.
In Joachim's variation, Black has captured two White stones, at c and at o.
The net effect is zero.

In KataGo's variation (at the right), White has one point of territory at e, which is compensated for by Black's point of territory at f.

Eventually, Black's additional point of territory inside his eye at c makes the difference.
The game – following Joachim's tesuji – now ends with W + 1!

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

There can only be one


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

Above we found that White's bad-shape move at a is no longer effective, as it is miai with the point of b.

My guzumi (triangled) remains the only effective bad-shape move in this problem :D

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

For your convenience follow the SGFs of both lines:





Attachments:
JoachimsO14AfterN13.sgf [3.81 KiB]
Downloaded 446 times
KataGosF9.sgf [3.52 KiB]
Downloaded 439 times

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The really most difficult Go problem ever: http://igohatsuyoron120.de/index.htm
Igo Hatsuyoron #120 (still unresolved by professionals, maybe solved by four amateurs)


Last edited by Cassandra on Fri Dec 13, 2019 1:53 am, edited 1 time in total.
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Post #35 Posted: Mon Dec 09, 2019 5:17 pm 
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I think what y'all are doing is marvelous. :) I haven't studied it to speak of, but there is something here I don't understand. You say that Black147 is sente. OK. I gather that the reason is that White cannot allow Black to make two eyes.

Click Here To Show Diagram Code
[go]$$Wcm146
$$ +---------------------------------------+
$$ | . . . X O O . . . . . X X X O . O X . |
$$ | . . . X X O O X O O . X O X O . . O . |
$$ | . . . X O X O O . . O X O O . O O . . |
$$ | . X O , . X X X O O . X . O O X . . . |
$$ | . . X X X X O O O . O X X O X X O O . |
$$ | . X . O O O X X X O . . X X X O O . . |
$$ | O O O O O X O O X X O O X . X . . X . |
$$ | O X . X . X O O O X O 2 W X X X X X X |
$$ | O X . X X X X O X X O 3 X X X X O O O |
$$ | X O O X . X O O X O O X X O O O O X . |
$$ | X X O O X O O O X O . X O O O . X X X |
$$ | X X . O X O X O X O . X O O X X X O O |
$$ | X X O O X X X O X O . X O O O X X X O |
$$ | X O O O O X . O X O . X X O O O X O O |
$$ | X O X O X X . O X O X . O X X X O O O |
$$ | O X X X X X . O X O O O O X O X O O X |
$$ | O . . . O X O O X X X X X . O X X O X |
$$ | O X X . X O . O O O O O O X O X . O X |
$$ | . X . . X O O O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]


Just in this little local area Black has captured the :wc: stone, for one point, but White, unless there is something special about this ko, has ⅓ point, on average, towards capturing the Black stone. On average, then, Black has ⅔ pt. However, IIUC, a dame is worth one pt. for Black, and White148 has filled that dame. That means that Black really has, on average, -⅓ pt., while if White simply saves the :wc: stone, Black has 0 pts. and still has the dame. That is, Black147 is a losing sente and Black should not play it. (We're behind the looking glass, but there you go. ;))

Now, if Black does not play B147 here, White, later on, may fill the dame without saving the :wc: stone. In that case the play may go this way locally.

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


In this case Black takes the ko later rather than sooner, and, as we know, that may be important in a semeai.

So, from what little I understand, it looks like Black147 is a mistake.

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Post #36 Posted: Mon Dec 09, 2019 7:43 pm 
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Many thanks, Bill, for clarifying this technical issue.

"Ko" is one of my very blind spots.

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The really most difficult Go problem ever: http://igohatsuyoron120.de/index.htm
Igo Hatsuyoron #120 (still unresolved by professionals, maybe solved by four amateurs)

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Post #37 Posted: Wed Dec 11, 2019 2:31 am 
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Too much noise for KataGo?

Click Here To Show Diagram Code
[go]$$Bcm143
$$ +---------------------------------------+
$$ | . . . X O O . . . . . X X X O . O X . |
$$ | . . . X X O O X O O . X O X O . . O . |
$$ | . . . X O X O O . . . X O O . O O . . |
$$ | . X O , . X X X O O . X . O O X . . . |
$$ | . . X X X X O O O . O X X . X X O O . |
$$ | . X . O O O X X X O . . X 1 X O O . . |
$$ | O O O O O X O O X X O O X O X . . X . |
$$ | O X . X . X O O O X O . O . X X X X X |
$$ | O X . X X X X O X X O . X X X X O O O |
$$ | X O O X . X O O X O O X X O O O O X . |
$$ | X X O O X O O O X O . X O O O . X X X |
$$ | X X . O X O X O X O . X O O X X X O O |
$$ | X X O O X X X O X O . X O O O X X X O |
$$ | X O O O O X . O X O . X X O O O X O O |
$$ | X O X O X X . O X O X . O X X X O O O |
$$ | O X X X X X . O X O O O O X O X O O X |
$$ | O . . . O X O O X X X X X . O X X O X |
$$ | O X X . X O . O O O O O O X O X . O X |
$$ | . X . . X O O O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]

Joachim's tesuji in the bamboo-joint seemed to be a quite unusual move, because KataGo did not even consider it, see "original.png" (green = KataGo's prefered move; red = other moves with displayed playouts).

Because the other considered moves were mainly part of the liberty-occupying part of the Main Semeai, so I wondered what would happen, if the other liberties are occupied first, and the bamboo-joint area is left untouched until shortly before the moment when the tail is captured.

The result of KataGo's analysis at this moment can be seen in "delayed.png".
Now, Joachim's tesuji is also KataGo's prefered move!!!

It seems to me that you must be very well aware of what you are doing when using KataGo as a very powerful tool for analysis.


Attachments:
original.png
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The really most difficult Go problem ever: http://igohatsuyoron120.de/index.htm
Igo Hatsuyoron #120 (still unresolved by professionals, maybe solved by four amateurs)

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Post #38 Posted: Wed Dec 18, 2019 11:00 am 
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Warning: The Semeai Variation is near!

White will choose the Capture Variation to realise her territorial gains at the left, due to KataGo's new atari / capture / connection.

However, if you want to evaluate variations, you have to be aware that the Semeai Variation might be nearer than expected. I had to learn this painfully ...

Click Here To Show Diagram Code
[go]$$B
$$ +-------------------------------------------------------------------------------+
$$ - . . . B O O . . . . O . . . O . O X . - . . . . X X W W . . O . . . O . O X . -
$$ - . . . B X O O X O O O . O . O . . O . - . . . . X O O . O O O . O . O . . O . -
$$ - . . . X O X O O . . O . O O O O O . . - . . . X . X X O . . O . O O O O O . . -
$$ - . X O , . X X X Q O O . O O O , O . . - . X O , X . X O . O O . O O O , O . . -
$$ - . . X X X X O O O . O . . O . . O O . - . . X X X X O O O . O . . O . . O O . -
$$ - X X X O O O X X X O Q O . . . O Q O O - X X X O O O X X X O . O . . . O . O O -
$$ - O O O O @ X O O X X O O . Q . O O . O - O O O O X X O O X X O O P O . O O . O -
$$ - O X X X B X O O O X O Q O . . . . . . - O X X X . X . O O X O . O P . . . . . -
$$ - O X X X B X X O X X O O . . . . O O O - O X X X . X . O X X O O . . . . O O O -
$$ - O O O X B X O O X O O . . O O O O X . - O O O X . X O O X O O . . O O O O X . -
$$ - O O O O X O O O X O O . O O O X X X X - X X O O X . . O X O O . O O O . X X X -
$$ - X X O O X O X O X O O . O O X X X . . - . O O O X . . O X O O . O O X X X . . -
$$ - . O O @ X X X O X O O . O O O X X X . - O O O X X . . O X O O . O O O X X X . -
$$ - O O O @ O X . O X O . . . O O O X . . - O O O X O X . O X O P . . O O O X . . -
$$ - O O X @ B X . O X O . O O X X X . . . - O O X . . X . O X O . O O X X X . . . -
$$ - O X X B B X . O X O O O O X . X . . X - O X X , X X . O X O O O O X . X . . X -
$$ - O X . . O X O O X X X X X X O X X . X - O X . . O X O O X X X X X X O X X . X -
$$ - O X X . X O . O O O O O O X . X X . X - O X X . X O . O O O O O O X . X X . X -
$$ - X X . . X O O O . . . . O X X X X . . - X X . . X O O O . . . . O X X X X . . -
$$ +-------------------------------------------------------------------------------+[/go]

In the diagrams above, we compare the final position of the Semeai Variations after KataGo's new moves (at the left) with that of Our Solution (at the right).

Legend:
Triangle = plus one point for Black
Square = plus two points for Black
Circle = minus one point for Black
Cross = minus two points for Black

There are 13 plus points for Black, but 16 minus points, so KataGo's variation is three points better than Our Solution.
Our Solution ended with three points for Black, so KataGo's Semeai Variation results in a drawn game. This is only ONE point worse than KataGo's Capture Variation.

+ + + + + + + + + +

An application case:
Let us assume that -- by some magic -- Black was able to reduce White's territory in the upper right by an additional point (without compensation), so that the Capture Variation would end in jigo.
However, Black invested an additional stone, so White will gain an additional prisoner = point when choosing the Semeai Variation, which then will give her the same one point win that she had before.

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Igo Hatsuyoron #120 (still unresolved by professionals, maybe solved by four amateurs)

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Post #39 Posted: Wed Dec 18, 2019 7:13 pm 
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Yeah, I had noticed in some of my explorations with KataGo that actually sometimes it chose the semeai variation (as winning for white) if you sufficiently much had black deviate in a few spots.

The thing is, some of white's gains on the left side costs white some turns or some liberties, but don't actually lose very much in the case that ultimately the semeai variation is chosen. If black spends those extra liberties pushing in the upper right, black improves the capture variation, but those moves *lose* points on the semeai variation.

So given that most of black's ability to balance white's gains comes at the cost of making one variation worse to improve the other, whereas some of white's gains just purely make one variation better without costing in the other, black starts to get squeezed in both variations.


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Post #40 Posted: Thu Dec 19, 2019 9:18 am 
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A 50 per cent approach-move liberty

Did you ever wonder why the score difference between the Capture Variation and the Semeai Variation with KataGo's new ( & amateurish enhanced) solution is odd (W + 1 vs. Jigo), while this difference was even with Our Solution (B + 5 / B + 3), as well as decades ago?

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

Well, the cause is the marked cutting point in the center, which is only valid to a limited extent. It will vanish, if White chooses the Capture Variation with a move at "a", but it will turn into an approach-move liberty, if White follows the Semeai Variation by continuing with a move at e.g. "b".

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

With the Capture Variation, this intersection becomes one point of White territory.

Click Here To Show Diagram Code
[go]$$Bc
$$ +---------------------------------------+
$$ | . . . X O O . . . . O X X X O . O X . |
$$ | . . . X X O O X O O O X O X O . . O . |
$$ | . . . X O X O O . . O X O O O O O . . |
$$ | . X O , . X X X O O . X O O O X O . . |
$$ | . . X X X X O O O . O X X O X X O O . |
$$ | X X X O O O X X X O M O X X X O O O O |
$$ | O O O O O X O O X X O O X C X O O X O |
$$ | O X X X X X O O O X O W O X X X X X X |
$$ | O X X X X X X O X X O O X X X X O O O |
$$ | O O O X X X O O X O O X X O O O O X . |
$$ | O O O O X O O O X O O X O O O . X X X |
$$ | X X O O X O X O X O c X O O X X X O O |
$$ | . O O O X X X O X O d X O O O X X X O |
$$ | O O O O O X . O X O B X X O O O X O O |
$$ | O O X O X X . O X O X O O X X X O O O |
$$ | O X X X X X . O X O O O O X . X O O X |
$$ | O X . . O X O O X X X X X X O X X O X |
$$ | O X X . X O . O O O O O O X . X . O X |
$$ | X X . . X O O O . . . . O X X X . O . |
$$ +---------------------------------------+[/go]

With the Semeai Variation, however, due to Black's eye at O13 (and his connection at L6, and White's vanished eye in the centre at M12), White is able to approach at c AND d, only after connecting at the crossed board point before. This connection costs her one point of territory, but in the Semeai Variation only.

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Igo Hatsuyoron #120 (still unresolved by professionals, maybe solved by four amateurs)

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