My initial feeling was also against letting bots use their latest version in tournaments that span a long time, but I suppose the humans are allowed to improve too (but not replace themselves with their twin/child/friend, so to what extent is a new version of DeepZen the same entity?).
Anyway, the opening of Chen Zijian vs. An Joyeong was rather puzzling to me. Following black's knight move at 19 An cut at 20, which is a standard thing to do in the local shape.
- Click Here To Show Diagram Code
[go]$$Bcm19
$$ +---------------------------------------+
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$$ | . . . O . . . . . , . . . . . X . . . |
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$$ | . . . . . . . . 1 . . . . . . . . . . |
$$ | . . . . . . . . . . O . . . . . . . . |
$$ | . . . . . . . . . X O . . . . X . . . |
$$ | . . X X . . . . . X . . . . . . 2 . . |
$$ | . . O , . . . . . , . O . . O , X . . |
$$ | . . . O . O . . . X . . . . O X . . . |
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$$ +---------------------------------------+[/go]
Later An pushed at 28 below, so Chen obviously played 29 in sente and white's shape suffered. Isn't it better for white to play at 29 himself first: if black blocks we usually think that's a good exchange as it means black can't increase his eyespace in sente like he did in the game, and means white can live by connecting there instead of crawling for ever, which also means black's corner isn't alive (locally it's a ko, but p2 hane and connect is sente for cutting point). Did An not like black ignoring and blocking at 28 if he played at 29? Taking the corner is ok isn't it? Maybe An meant to play there first but did the 1-2-3 mistake of imagining he had played the 1-2 exchange when he hadn't and playing 3 straight away? Or if white had previously cut at q7 (but here black has ladder) then crawling instead makes sense because if black plays in the corner then you can play one or more ataris to come up off the second line in sente before connecting.
- Click Here To Show Diagram Code
[go]$$Wcm28 An Joyeong (white) vs Chen Zijian
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$$ | . . . . . . . . X . . . . . . . X 1 . |
$$ | . . . . . . . . . . O . . . . . X O . |
$$ | . . . . . . . . . X O . . . . X O 3 . |
$$ | . . X X . . . . . X . . . . . X O . . |
$$ | . . O , . . . . . , . O . . O O X 2 . |
$$ | . . . O . O . . . X . . . . O X X . . |
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$$ +---------------------------------------+[/go]
So what happened is An had to crawl, and then played the descent. Apparently this was sente as black answered, I didn't yet read how to win the semeai if black turns on the outside instead. If white can get this point to stop black from living here (like what normally happens) I can see that is a plus for white.
- Click Here To Show Diagram Code
[go]$$Wcm36
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$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , X O . |
$$ | . . . . . . . . . . . . . . . . X O . |
$$ | . . . . . . . . X . . . . . . . X O . |
$$ | . . . . . . . . . . O . . . . . X O . |
$$ | . . . . . . . . . X O . . . . X O O . |
$$ | . . X X . . . . . X . . . . . X O . . |
$$ | . . O , . . . . . , . O . . O O X X . |
$$ | . . . O . O . . . X . . . . O X X . . |
$$ | . . . . . . . . . . . . . . 1 . . 2 . |
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$$ +---------------------------------------+[/go]
And then he jumped and crawled on the 2nd line some more, and eventually black came back to live. Isn't this an utter failure for white, with the kind of 2nd line crawl we scold 20 kyus for playing? I know AlphaGo famously crawled on the 2nd line against Park Junghwan, but this seems far worse than that, the black wall is hardly weak (though there is gap at
a and cut at
b to exploit). An then jumped out at 52, which is the move he probably wanted to do before starting all this sequence, and does somewhat reduce the influence of the huge wall he just gave to black. Thinking about the evaluation from Park's game, white has 7 real points (though the group died from a ko threat later), and black doesn't have many real points yet (top right corner fairly open with that peep stone and open on 1st line), but he only needs to get a territory of width 1 along the Q column next to his wall to get as many as white did.
- Click Here To Show Diagram Code
[go]$$Wcm50
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$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . O . . . . . , . . . . . X X X . |
$$ | . . . . . . . . . . . . . . . . X O 1 |
$$ | . . . . . . . . . . . . . . . . X O . |
$$ | . . . . . . . . . . . . . . . . a O . |
$$ | . . . . . . . . . . . . . . . . X O . |
$$ | . . . . . . . . . . . . . . . . X X O |
$$ | . . . , . . . . . , . . . . . , X O . |
$$ | . . . . . . . . . . 3 . . . . . X O . |
$$ | . . . . . . . . X . . . . . . . X O . |
$$ | . . . . . . . . . . O . . . . b X O . |
$$ | . . . . . . . . . X O . . . . X O O . |
$$ | . . X X . . . . . X . . . . . X O . . |
$$ | . . O , . . . . . , . O . . O O X X . |
$$ | . . . O . O . . . X . . . . O X X . . |
$$ | . . . . . . . . . . . . . . O 2 . X . |
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$$ +---------------------------------------+[/go]