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Pros inspired by AlphaGo
http://lifein19x19.com/viewtopic.php?f=13&t=12953		 Page 1 of 2
Author:  Uberdude [ Thu Mar 31, 2016 7:14 am ]
Post subject:  Pros inspired by AlphaGo
We've already seen quite a few games in which pros have played openings from the recent Lee Sedol vs AlphaGo match so I thought I'd start a thread to collect, discuss and analyze them rather than derailing other threads.

For starters we have Park Junghwan and Ke Jie in their Tygem match game 6 following AlphaGo game 2. Ke playing black (AlphaGo) deviated first and Park won that game. See viewtopic.php?p=201496#p201496.

Then in the 11th Chunlan Cup we had Park Junghwan (white, AlphaGo) vs Mi Yuting copying AlphaGo game 5. Mi (black, Lee) deviated first with a small kikashi exchange that seems to improve on Lee's play, then Park made a small not large knight's enclosure, and then Mi deviated significantly by taking the top left corner in sente and then preventing the white top moyo, whereas Lee played on the outside to prevent the wall but took gote allowing AlphaGo to build the big moyo. Park as white lost that game which AlphaGo won, but the pro commentary seems to be that the opening was good for him but he made mistakes in later fighting which failed to utilise his thickness effectively. Quite a lot of discussion on that game over here: viewtopic.php?p=201776#p201776.

And now today in the Asian TV Cup prelims we have Shin Jinseo (black, Lee Sedol) vs Heo Yongho playing AlphaGo game 5 again (but with 3-4 not 4-4 at top left), and black wins this one. Black plays q10 rather than o7 which allows white to squeeze from the centre but not the side and the game goes into a running fight when black resists the crosscut sacrifice on the top right corner:
Author:  yoyoma [ Thu Mar 31, 2016 9:48 am ]
Post subject:  Re: Pros inspired by AlphaGo
In the other thread we discussed Park Junghwan vs Mi Yuting game some, I found a Korean article talking about it with some thoughts on the upper left corner from both Lee Sedol and Park Junghwan. Go to move 32/33.



Lee Sedol said he didn't play C17 because he thought AlphaGo would play this way (see sgf), and then Black must play here next. He thought this would be complicated and wasn't confident about it, so he picked a different method. But now in this game Park Junghwan has the chance to play the line Lee Sedol feared... And Park Junghwan likewise decided it was too complicated, and also chose a different way. So both players saw the same variation, but didn't play it due to it being too complicated. Lee Sedol also said that for his game, he didn't think this part of the game was too important.

I don't think the article really has any conclusion about what the best way to play is, just pointing out what the players were thinking.

Original Korean article here
http://www.cyberoro.com/news/news_view. ... =1&cmt_n=0
Author:  ez4u [ Thu Mar 31, 2016 3:45 pm ]
Post subject:  Re: Pros inspired by AlphaGo
yoyoma wrote:
In the other thread we discussed Park Junghwan vs Mi Yuting game some, I found a Korean article talking about it with some thoughts on the upper left corner from both Lee Sedol and Park Junghwan. Go to move 32/33.

[edited to replace sgf with the relevant diagram]
Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 1 . . O . . . . . . . . X . . . . |
$$ | . X . O a . . . . , . . . . . , X X . |
$$ | . . 3 . . . . . . . . . . . O X O . . |
$$ | . . X 2 . . . . . . . . . . . O O . . |
$$ | . . . 4 . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . , O X . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . O X X . . |
$$ | . . . . . . . . . . . . . X X O . . . |
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . O . . . . . , . . . . . , X . . |
$$ | . . . . . O . . . . . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Lee Sedol said he didn't play C17 because he thought AlphaGo would play this way (see sgf[see diagram]), and then Black must play here next ['a' in the diagram]. He thought this would be complicated and wasn't confident about it, so he picked a different method. But now in this game Park Junghwan has the chance to play the line Lee Sedol feared... And Park Junghwan likewise decided it was too complicated, and also chose a different way. So both players saw the same variation, but didn't play it due to it being too complicated. Lee Sedol also said that for his game, he didn't think this part of the game was too important.

I don't think the article really has any conclusion about what the best way to play is, just pointing out what the players were thinking.

Original Korean article here
http://www.cyberoro.com/news/news_view. ... =1&cmt_n=0

I wish that Lee Sedol's comments here had been a little more in depth. Although 'a' above [1 below] is the most common local continuation for Black in this joseki, normally he just plays elsewhere. If Black does play 'a', the normal continuation is pretty straightforward.
Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . 9 O . . . . . . . . X . . . . |
$$ | . X . O 1 2 . . . , . . . . . , X X . |
$$ | . . X . 3 4 . . . . . . . . O X O . . |
$$ | . . X O 5 7 8 . . . . . . . . O O . . |
$$ | . . . O . 6 0 . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . , O X . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . O X X . . |
$$ | . . . . . . . . . . . . . X X O . . . |
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . O . . . . . , . . . . . , X . . |
$$ | . . . . . O . . . . . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


So why did Lee think that he would have to continue at 'a' here when usually he doesn't and what complex alternatives to normal play was he anticipating?
:scratch:
Author:  Uberdude [ Thu Mar 31, 2016 10:37 pm ]
Post subject:  Re: Pros inspired by AlphaGo
ez4u wrote:
So why did Lee think that he would have to continue at 'a' here when usually he doesn't and what complex alternatives to normal play was he anticipating?

Presumably that white would not sacrifice for the gote thickness, but save the stone in a complicated fight:
Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 7 6 . . . . . . . . . . . . . . . . |
$$ | . . X 2 . O . . . . . . . . X . . . . |
$$ | . X . O 1 5 8 . . , . . . . . , X X . |
$$ | . . X 3 4 . . . . . . . . . O X O . . |
$$ | . . X O . . . . . . . . . . . O O . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . , O X . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . O X X . . |
$$ | . . . . . . . . . . . . . X X O . . . |
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . O . . . . . , . . . . . , X . . |
$$ | . . . . . O . . . . . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Kim Myungwan 9p made the comment the AlphaGo likes to make the first crosscut and fight very early, perhaps even more so than Lee Sedol.
Author:  Lucian [ Sun Apr 03, 2016 1:26 am ]
Post subject:  Re: Pros inspired by AlphaGo
In today 3rd round from LG qualifications Choi Cheolhan play an exciting game, with an AlphaGo-esque fuseki. It's the first time I see him trying the irregular 3-13 combination. I felt that the second half of the game was very steady for Black, also reminiscent of AlphaGo style. In the end Black had a comfortable 4-5 points win.

Author:  macelee [ Sun Apr 03, 2016 7:56 am ]
Post subject:  Re: Pros inspired by AlphaGo
Sorry but I don't agree with your assessment of the second half. It's clear to me that W136 is too small - B14 is much a larger yose move. The move is at least reverse sente of 8 points (I have not even counted the extra value at E14. B139 was a good move. If white played B14, black does not seem to have any lead at all.
Author:  Lucian [ Sun Apr 03, 2016 12:39 pm ]
Post subject:  Re: Pros inspired by AlphaGo
macelee wrote:
Sorry but I don't agree with your assessment of the second half. It's clear to me that W136 is too small - B14 is much a larger yose move. The move is at least reverse sente of 8 points (I have not even counted the extra value at E14. B139 was a good move. If white played B14, black does not seem to have any lead at all.


Please share with us if you have seen any post-game analysis by professionals for this game, I am really curious :). I am a much much weaker player of course than both these players, so I don't know what were White mistakes that made that +/- 4.5 points difference when he resigned. I also didn't claim that I evaluated or assessed the position, I said that I "felt".

That being said, for the sake of analysis at 5 dan amateur level:

1) If you say "The move is at least reverse sente of 8 points..." it seems that it was anyway Black privilege to play the sequence from the game, so by giving White a chance to play it at 136, Black made first a "mistake" of timing.

2) Was really 136 the losing move? Assuming White plays at 136 the B14 - B15 connection, locally Black can play the forcing moves at E7 and E6 and then block at B7. White will probably have to take the E4 stone, otherwise when Black connects at E5 A) he has the very big B5 continuation (if White C5, Black can continue at B4, White B3, Black connects and White will end with 5 points in the corner, in gote) B)He has some forcing moves in the center to force White to make the second eye for his center cut group.
If White takes the E4 stone, Black will get to play the A6 first line move.
Author:  Uberdude [ Wed May 04, 2016 1:37 am ]
Post subject:  Re: Pros inspired by AlphaGo
Lee Sedol has been in good form since the AlphaGo match, with a 6 game winning streak which has seen him qualify for the semi-final of the Ing Cup and just today he won the first game of the Maxim cup final against Won Sungjin. His Ing quarter-final win against Kang Dongyun featured some rather AlphaGo-esque centre play around move 21. The following sequence in which he sacrificed the centre n7 cutting stones and left the others as junk in exchange for a large solid lower right corner was rather hard for me to understand but showed great flexibility. He later used the aji of those junk stones nicely. In this recent Korean article Lee says how he has learned from AlphaGo to be more flexible and be less indulgent in his reading and expectations of his opponents' moves.



And here is his win against Won in the Maxim cup today. He played very actively and flexibly in the opening.
Author:  gamesorry [ Wed May 04, 2016 11:20 am ]
Post subject:  Re: Pros inspired by AlphaGo
It took me quite some time to understand why W154 is needed in the Lee-Weon game :D
Author:  macelee [ Wed May 04, 2016 11:42 am ]
Post subject:  Re: Pros inspired by AlphaGo
gamesorry wrote:
It took me quite some time to understand why W154 is needed in the Lee-Weon game :D


Can you please explain more? I read that W154 is a slack move.
Author:  Lucian [ Wed May 04, 2016 12:27 pm ]
Post subject:  Re: Pros inspired by AlphaGo
macelee wrote:
gamesorry wrote:
It took me quite some time to understand why W154 is needed in the Lee-Weon game :D


Can you please explain more? I read that W154 is a slack move.


It looks like with the proper move order, white must give the tail of his group: Black P5 White P6 Black T5 White S4 and Black P4 finishes the sequence. There are many variations, maybe I am missing some move for White, but it seems Black can exploit the White damezumari.
Author:  macelee [ Wed May 04, 2016 1:50 pm ]
Post subject:  Re: Pros inspired by AlphaGo
Lucian wrote:
macelee wrote:
gamesorry wrote:
It took me quite some time to understand why W154 is needed in the Lee-Weon game :D


Can you please explain more? I read that W154 is a slack move.


It looks like with the proper move order, white must give the tail of his group: Black P5 White P6 Black T5 White S4 and Black P4 finishes the sequence. There are many variations, maybe I am missing some move for White, but it seems Black can exploit the White damezumari.


Your reading is correct. P4 is really a good move.

[edit] sorry my earlier comment was wrong
Author:  Uberdude [ Thu May 05, 2016 1:41 am ]
Post subject:  Re: Pros inspired by AlphaGo
When I whizzed through the game I too was a bit surprised that 154 was needed, here is the sequence I think we are talking about in diagram form.

Click Here To Show Diagram Code
[go]$$Bc If white tenukis, say to top right corner...
$$ +---------------------------------------+
$$ | . . . . . . . O . . . . . . . . . . . |
$$ | . X O . . X O . O . O O . . . . . . . |
$$ | . X X O . . X O . X O X . O . . 2 . . |
$$ | . X O , . . X . . O X O . . . X . . . |
$$ | . . . O X . . . . O X . . . . . . . . |
$$ | . . X X . . . . O X O . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 1 . . |
$$ | . . . , . . . . . , . . . . . , . X . |
$$ | . . . O O . . . . . . . X . . X X O . |
$$ | . . O X X . . . . . . O . . . . O . O |
$$ | . . O O X O . . O . . O X X . X X O O |
$$ | . O O X X O . O . O O X O . 4 . . . . |
$$ | . X O X O O X O O X X X O . 3 O O O 5 |
$$ | X . X O . O . X O X O O O . 7 O X 6 O |
$$ | . . X O O X X X X X X X O O O X X X O |
$$ | . . X X O X . X . X X . O X X X X . X |
$$ | . . . . O . . . X X . . . O . . . X . |
$$ +---------------------------------------+[/go]


Click Here To Show Diagram Code
[go]$$Wm8 variation 1, 10 is self-atari, so 11 captures
$$ +---------------------------------------+
$$ | . . . . . . . O . . . . . . . . . . . |
$$ | . X O . . X O . O . O O . . . . . . . |
$$ | . X X O . . X O . X O X . O . . O . . |
$$ | . X O , . . X . . O X O . . . X . . . |
$$ | . . . O X . . . . O X . . . . . . . . |
$$ | . . X X . . . . O X O . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . X . |
$$ | . . . O O . . . . . . . X . . X X O . |
$$ | . . O X X . . . . . . O . . . . O . O |
$$ | . . O O X O . . O . . O X X . X X O O |
$$ | . O O X X O . O . O O X O 1 O 4 3 2 . |
$$ | . X O X O O X O O X X X O . X O O O X |
$$ | X . X O . O . X O X O O O . X O X O O |
$$ | . . X O O X X X X X X X O O O X X X O |
$$ | . . X X O X . X . X X . O X X X X . X |
$$ | . . . . O . . . X X . . . O . . . X . |
$$ +---------------------------------------+[/go]



Click Here To Show Diagram Code
[go]$$Wm8 variation 2, white can't play 12 at 13 to avoid the false eye as it's self-atari again.
$$ +---------------------------------------+
$$ | . . . . . . . O . . . . . . . . . . . |
$$ | . X O . . X O . O . O O . . . . . . . |
$$ | . X X O . . X O . X O X . O . . O . . |
$$ | . X O , . . X . . O X O . . . X . . . |
$$ | . . . O X . . . . O X . . . . . . . . |
$$ | . . X X . . . . O X O . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . X . |
$$ | . . . O O . . . . . . . X . . X X O . |
$$ | . . O X X . . . . . . O . . . . O . O |
$$ | . . O O X O . . O . . O X X . X X O O |
$$ | . O O X X O . O . O O X O 2 O 1 6 4 5 |
$$ | . X O X O O X O O X X X O 3 X O O O X |
$$ | X . X O . O . X O X O O O . X O X O O |
$$ | . . X O O X X X X X X X O O O X X X O |
$$ | . . X X O X . X . X X . O X X X X . X |
$$ | . . . . O . . . X X . . . O . . . X . |
$$ +---------------------------------------+[/go]


Note how it's crucial that black plays p4 directly, not preceded by o6.
Author:  Lucian [ Thu May 05, 2016 10:32 am ]
Post subject:  Re: Pros inspired by AlphaGo
Uberdude wrote:
When I whizzed through the game I too was a bit surprised that 154 was needed, here is the sequence I think we are talking about in diagram form.


If you took the trouble to put it in nice diagrams, don't forget the one when White sacrifices the tail in order to live: after Black P4, White plays directly R6. Just for reference :)
Author:  ez4u [ Thu May 05, 2016 8:17 pm ]
Post subject:  Re: Pros inspired by AlphaGo
@Uberdude
How about this 10? Black suffers from shortage of liberties on both sides.
Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . O . . . . . . . . . . . |
$$ | . X O . . X O . O . O O . . . . . . . |
$$ | . X X O . . X O . X O X . O . . O . . |
$$ | . X O , . . X . . O X O . . . X . . . |
$$ | . . . O X . . . . O X . . . . . . . . |
$$ | . . X X . . . . O X O . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . X . |
$$ | . . . O O . . . . . . . X . . X X O . |
$$ | . . O X X . . . . . . O . . . . O . O |
$$ | . . O O X O . . O . . O X X 0 X X O O |
$$ | . O O X X O . O . O O X O 7 2 6 . 9 . |
$$ | . X O X O O X O O X X X O 8 1 O O O 3 |
$$ | X . X O . O . X O X O O O . 5 O X 4 O |
$$ | . . X O O X X X X X X X O O O X X X O |
$$ | . . X X O X . X . X X . O X X X X . X |
$$ | . . . . O . . . X X . . . O . . . X . |
$$ ---------------------------------------[/go]
Author:  Vesa [ Thu May 05, 2016 9:44 pm ]
Post subject:  Re: Pros inspired by AlphaGo
ez4u wrote:
@Uberdude
How about this 10? Black suffers from shortage of liberties on both sides.
Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . O . . . . . . . . . . . |
$$ | . X O . . X O . O . O O . . . . . . . |
$$ | . X X O . . X O . X O X . O . . O . . |
$$ | . X O , . . X . . O X O . . . X . . . |
$$ | . . . O X . . . . O X . . . . . . . . |
$$ | . . X X . . . . O X O . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . X . |
$$ | . . . O O . . . . . . . X . . X X O . |
$$ | . . O X X . . . . . . O . . . . O . O |
$$ | . . O O X O . . O . . O X X 0 X X O O |
$$ | . O O X X O . O . O O X O 7 2 6 . 9 . |
$$ | . X O X O O X O O X X X O 8 1 O O O 3 |
$$ | X . X O . O . X O X O O O . 5 O X 4 O |
$$ | . . X O O X X X X X X X O O O X X X O |
$$ | . . X X O X . X . X X . O X X X X . X |
$$ | . . . . O . . . X X . . . O . . . X . |
$$ ---------------------------------------[/go]

After black 1, how would you continue? Profit for black?

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


Or perhaps the earlier 7-8 exchange can be omitted?

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


Cheers,
Vesa
Author:  Uberdude [ Fri May 06, 2016 11:08 am ]
Post subject:  Re: Pros inspired by AlphaGo
Lucian wrote:
If you took the trouble to put it in nice diagrams, don't forget the one when White sacrifices the tail in order to live: after Black P4, White plays directly R6. Just for reference :)

Click Here To Show Diagram Code
[go]$$Wm8 variation 3, sacrifice the tail
$$ +---------------------------------------+
$$ | . . . . . . . O . . . . . . . . . . . |
$$ | . X O . 7 X O . O . O O . . . b f d . |
$$ | . X X O . . X O . X O X . O . a O e . |
$$ | . X O , 5 . X . . O X O . . . X c . . |
$$ | . . . O X 6 . . . O X . . . . . . . . |
$$ | . . X X . . . . O X O . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . X . |
$$ | . . . O O . . . . . . . X . . X X O . |
$$ | . . O X X . . . . . . O . . . . O . O |
$$ | . . O O X O . . O . . O X X . X X O O |
$$ | . O O X X O . O . O O X O 4 O 2 1 . 3 |
$$ | . X O X O O X O O X X X O . X O O O . |
$$ | X . X O . O . X O X O O O . X O X O O |
$$ | . . X O O X X X X X X X O O O X X X O |
$$ | . . X X O X . X . X X . O X X X X . X |
$$ | . . . . O . . . X X . . . O . . . X . |
$$ +---------------------------------------+[/go]

So if the defence was slow (was that the judgement of some Chinese pro analysis macelee read that correctly saw p4 and the possibility of this trade?) that's saying this trade is better for white, give the tail and take the top left instead (I think top right is biggest (I think we can assume a-f), then top left (which isn't sente but if black omits c11 then white can hassle the eyeshape a bit following c12) and then centre). It's quite hard to count the difference as in the game soon after the top left sequence white came back to answer the top right corner attach, which meant Weon got that in sente which is pretty nice (though of course bad aji from that p18 hane connect remains as the game winning sequence shows).

And regarding ez4u / Vesa, it does look better to not push with 7-8 doesn't it, as then black can keep the white chain to 3 liberties (if white pushes out above 8 in Vesa's last diagram black can now just block and doesn't lose the 3 stones) and the killing/trade sequence remains. Another important move order technique!
Author:  Granlund [ Sat May 07, 2016 5:57 am ]
Post subject:  Re: Pros inspired by AlphaGo
Uberdude wrote:
And regarding ez4u / Vesa, it does look better to not push with 7-8 doesn't it, as then black can keep the white chain to 3 liberties (if white pushes out above 8 in Vesa's last diagram black can now just block and doesn't lose the 3 stones) and the killing/trade sequence remains. Another important move order technique!

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


How does black block?
Author:  Uberdude [ Sat May 07, 2016 8:52 am ]
Post subject:  Re: Pros inspired by AlphaGo
My mistake, I was thinking p9 block and then white can't capture the o7 stones like he could before, but he can still get o6 in sente which is enough to live. So if all black can capture is the 5 white stones on the right edge then it does seem the kosumi was slow. But maybe there is a better move order for black?
Author:  Uberdude [ Tue May 10, 2016 2:28 am ]
Post subject:  Re: Pros inspired by AlphaGo
And today Lee Sedol just beat Won Sungjin again to extend his winning streak to 7 games and win the Maxim cup, his first title since the AlphaGo match.
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