Here is the game between Mi Yuting and Park Junghwan that starts the same as AlphaGo game 5. Although Mi (black) varies from Lee Sedol on move 25 I think that is Park who makes the more substantial deviation for 28 (f3 not g3). The s10 r11 exchange looks like a slight refinement by Mi on Lee's direct s6, as it means the squeeze that AlphaGo played isn't as good. The downside is the r11 area gets stronger but black is unlikely to want to invade there. So Mi is saying Lee made a slight mistake and showing a more refined sequence, and then Park makes the tighter corner enclosure which is quite different.
11th Chunlan Cup
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Uberdude
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yoyoma
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Re: 11th Chunlan Cup
The next change after the two you mentioned is Black 33 went into the corner instead of attaching on the outside at D12. The black got sente to play 41 at N17, limiting the top side potential. This sequence from move 33-41 seemed to have a larger impact on the game than the first two change you mentioned. It looks like a large improvement to me but what do I know. 
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MinjaeKim
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Re: 11th Chunlan Cup
Tygem and Oro news says the opening was a success for white, and the game is where white can make good use of his thinkness. However white failed to fully utilize his thickness in the middle game attack, and when the fights were settled, the game was comfortable for black who started with more territory.
I'm now waiting for the BadukTV website to upload their VOD of this game, which takes a few days, so that I can hear more about how the pros think about this Alphago's opening. I will share some notes and variations here.
I'm now waiting for the BadukTV website to upload their VOD of this game, which takes a few days, so that I can hear more about how the pros think about this Alphago's opening. I will share some notes and variations here.
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Uberdude
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Re: 11th Chunlan Cup
Interesting info MinjaeKim, it certainly felt like a huge failure for Park when Mi managed to both save his big dragon coming out from the lower side and the left side group in a profitable way with the capture of those 2 stones. c10 and white's honte answer puzzled me a bit, was black aiming at b12 or d12 if white ignored?
I recall the AlphaGo commentaries saying Lee attached rather than taking the top left corner to avoid the thickness as he must have thought that was too good for white and they seemed to concur.
Something I was thinking about from the 5th AlphaGo game was why Lee Sedol pushed with
as below. By loosing that liberty the n6 cut etc became more potent even though in the end white only got a squeeze (though actually given Mi's s10 attach I wonder if that squeeze really was a misread from AlphaGo or a sente sequence to stop Lee successfully playing that attach at a time when white would need to answer submissively as Park did, i.e. did AlphaGo see a line for black in which he played s10 and that reduced AlphaGo's winning chances so it played out the squeeze so Lee wouldn't have the chance to s10?).
If black directly haned and this happened that looks like an unconditional improvement to me (actually the improvement might not be so much as white could still probe with the n6 cut or s7 hane and if black plays in a way that makes the o8 liberty sente then white fixes that cut in sente which makes a big difference to the strength of the centre moyo, and if plays to prevent o8 being sente white gets the same squeeze...).
So did Lee fear white would trade with something like this? White abandons the top right moyo area (which makes sense as he hasn't yet invested building it with the a attach and subsequent gote building of thickness).
I recall the AlphaGo commentaries saying Lee attached rather than taking the top left corner to avoid the thickness as he must have thought that was too good for white and they seemed to concur.
Something I was thinking about from the 5th AlphaGo game was why Lee Sedol pushed with
as below. By loosing that liberty the n6 cut etc became more potent even though in the end white only got a squeeze (though actually given Mi's s10 attach I wonder if that squeeze really was a misread from AlphaGo or a sente sequence to stop Lee successfully playing that attach at a time when white would need to answer submissively as Park did, i.e. did AlphaGo see a line for black in which he played s10 and that reduced AlphaGo's winning chances so it played out the squeeze so Lee wouldn't have the chance to s10?).If black directly haned and this happened that looks like an unconditional improvement to me (actually the improvement might not be so much as white could still probe with the n6 cut or s7 hane and if black plays in a way that makes the o8 liberty sente then white fixes that cut in sente which makes a big difference to the strength of the centre moyo, and if plays to prevent o8 being sente white gets the same squeeze...).
So did Lee fear white would trade with something like this? White abandons the top right moyo area (which makes sense as he hasn't yet invested building it with the a attach and subsequent gote building of thickness).
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wineandgolover
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Re: 11th Chunlan Cup
Uber, in your last diagram, I think white can just pull back with the ataried stone, then block with the next move if black pushes through. Right? If so this looks way too good for white. And that explains black 43.
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Want to see videos of low-dan mistakes and what to learn from them? Brady's Blunders
Want to see videos of low-dan mistakes and what to learn from them? Brady's Blunders
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Uberdude
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Re: 11th Chunlan Cup
Like so? Black does feel a bit dumb capturing only those 2 stones as below now doesn't he?
But is this the best way for black, maybe 55 could push at 56? This direct cut looks better if white solidly connects as black can poke his head out and white can't run the 2 stones, so we probably expect the a-b exchange latter, or maybe black can get fancy and kikashi with c-d before b. This is definitely better for black than the last diagram, but is it better for black overall? Maybe? Would white e be next?
Or would white extend like this? Black now could choose to play a rather than the other atari to make 52 a dumb empty triangle later and save the centre cutting stones. But what is the next move now? If push at b will white hane or extend? Capture or c seem soft.
But is this the best way for black, maybe 55 could push at 56? This direct cut looks better if white solidly connects as black can poke his head out and white can't run the 2 stones, so we probably expect the a-b exchange latter, or maybe black can get fancy and kikashi with c-d before b. This is definitely better for black than the last diagram, but is it better for black overall? Maybe? Would white e be next?
Or would white extend like this? Black now could choose to play a rather than the other atari to make 52 a dumb empty triangle later and save the centre cutting stones. But what is the next move now? If push at b will white hane or extend? Capture or c seem soft.
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Uberdude
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macelee
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Re: 11th Chunlan Cup
I quote Uberdude's second diagram here:
I actually think black is not bad here. Eating two stones does not look very large at the first sight. But it has several benefits that can be easily underestimated: (1) the squeeze is gone so black actually gets many more points. (2) white's wall is not perfect with aji at L9. (3) most importantly, the attach at 'a' becomes less effective for white (yes, believe me that is related as I will explain). (4) following (3) if white's 'a' is not very serious, black can first reduce the bottom left corner at C3 or C4 as he has sente.
This is the real game: white got a very solid shape after
, black had to reduce at 
which as the game turned out was not an easy fight. How many of you have wondered why 
could not capture that stone instead to prevent white from sealing the top side? Here is why:
If captures, first of all black cannot fight a ko there because white has many ko threats near the squeeze (assuming AlphaGo knows how to fight ko properly 
). So black has to connect at 
. Locally black can defend the corner without problem. However, white can get 
in sente. As a result, this would happen ......
I will leave you guys to decode the sequence, but basically with the sente in the previous diagram, white can connect from the first line!
To summarise, in Uberdude's diagram, it may look like that capturing two stones are not quite big, but in fact it is much bigger because white's top side indirectly affected and reduced in value.
So back to the Chunlan Cup game, we can see Mi Yuting's S10/R11 exchange actually makes sense!
I actually think black is not bad here. Eating two stones does not look very large at the first sight. But it has several benefits that can be easily underestimated: (1) the squeeze is gone so black actually gets many more points. (2) white's wall is not perfect with aji at L9. (3) most importantly, the attach at 'a' becomes less effective for white (yes, believe me that is related as I will explain). (4) following (3) if white's 'a' is not very serious, black can first reduce the bottom left corner at C3 or C4 as he has sente.
This is the real game: white got a very solid shape after
, black had to reduce at which as the game turned out was not an easy fight. How many of you have wondered why could not capture that stone instead to prevent white from sealing the top side? Here is why:
= If
captures, first of all black cannot fight a ko there because white has many ko threats near the squeeze (assuming AlphaGo knows how to fight ko properly ). So black has to connect at . Locally black can defend the corner without problem. However, white can get in sente. As a result, this would happen ......I will leave you guys to decode the sequence, but basically with the
sente in the previous diagram, white can connect from the first line!To summarise, in Uberdude's diagram, it may look like that capturing two stones are not quite big, but in fact it is much bigger because white's top side indirectly affected and reduced in value.
So back to the Chunlan Cup game, we can see Mi Yuting's S10/R11 exchange actually makes sense!
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Uberdude
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Re: 11th Chunlan Cup
Nice sequence macelee, Go Seigen would be proud of that 1st line crawling! I wonder if any such sequences appeared in AlphaGo's playouts and that is why it didn't make the s10 t9 exchange. I don't think there was any time Lee could have exchanged s10 for r11 later in the game was there (too small), so it seems Mi has found the correct timing. Is it overly harsh on Lee to say that he should have found s10 in the game? Hindsight is nice, the games had a lot of pressure and 2 hours is not much time to think, but for a top top pro such as himself they should pay attention to the tiniest details and efficiencies.
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macelee
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Re: 11th Chunlan Cup
I am sure the first-line move was discovered by a Chinese pro during one of their regular group studies. I read it from some discussions on the Internet. Given the hint, even amateurs at our level can read through. But getting that strategy in the first place is much more difficult. I think it is highly unlikely that an AI program can 'plan' for something like that.
A pro player's thinking process would be something like: I read this variation; it doesn't seem to work; but if there's an extra stone there my sequence would work; let me find out a way to place that extra stone without my opponent noticing...... If a machine can do this sort of trick, our humanbeing would be wiped out soon.
A pro player's thinking process would be something like: I read this variation; it doesn't seem to work; but if there's an extra stone there my sequence would work; let me find out a way to place that extra stone without my opponent noticing...... If a machine can do this sort of trick, our humanbeing would be wiped out soon.
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Uberdude
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Re: 11th Chunlan Cup
macelee wrote:A pro player's thinking process would be something like: I read this variation; it doesn't seem to work; but if there's an extra stone there my sequence would work; let me find out a way to place that extra stone without my opponent noticing...... If a machine can do this sort of trick, our humanbeing would be wiped out soon.
Reminds me of Ma Xiaochun's 36 Stratagems book, all sorts of brilliant sneaky plans like that.
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Uberdude
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Re: 11th Chunlan Cup
Fan Hui gave a talk about AlphaGo vs Lee Sedol game 5 at the US Go Congress (https://www.youtube.com/watch?v=cmK2HwKMrco), which answered some questions I posed in the above. Lee's push rather than direct hane does indeed seem to be a mistake, and his fear of the double hane may well explain it. But AlphaGo would have simply extended with 3 as below if he played hane, not double hane! (possible continuation a-f shown too)Uberdude wrote: Something I was thinking about from the 5th AlphaGo game was why Lee Sedol pushed with
If black directly haned and this happened that looks like an unconditional improvement to me (actually the improvement might not be so much as white could still probe with the n6 cut or s7 hane and if black plays in a way that makes the o8 liberty sente then white fixes that cut in sente which makes a big difference to the strength of the centre moyo, and if plays to prevent o8 being sente white gets the same squeeze...).
So did Lee fear white would trade with something like this? White abandons the top right moyo area (which makes sense as he hasn't yet invested building it with the a attach and subsequent gote building of thickness).
Fan also showed the 1st line connection from the lower right dead stones to the upper right corner aji depending how black answers the crosscut there, though didn't say if AlphaGo saw those lines or just post-game professional analysis. No mention of Mi Yuting's s10 attachment though. Let's see what is in their release of commented games in a few weeks...
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ez4u
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Re: 11th Chunlan Cup
What was the explanation for rejecting the double hane?Uberdude wrote:Fan Hui gave a talk about AlphaGo vs Lee Sedol game 5 at the US Go Congress (https://www.youtube.com/watch?v=cmK2HwKMrco), which answered some questions I posed in the above. Lee's push rather than direct hane does indeed seem to be a mistake, and his fear of the double hane may well explain it. But AlphaGo would have simply extended with 3 as below if he played hane, not double hane! (possible continuation a-f shown too)Uberdude wrote: Something I was thinking about from the 5th AlphaGo game was why Lee Sedol pushed with
If black directly haned and this happened that looks like an unconditional improvement to me (actually the improvement might not be so much as white could still probe with the n6 cut or s7 hane and if black plays in a way that makes the o8 liberty sente then white fixes that cut in sente which makes a big difference to the strength of the centre moyo, and if plays to prevent o8 being sente white gets the same squeeze...).
So did Lee fear white would trade with something like this? White abandons the top right moyo area (which makes sense as he hasn't yet invested building it with the a attach and subsequent gote building of thickness).
Fan also showed the 1st line connection from the lower right dead stones to the upper right corner aji depending how black answers the crosscut there, though didn't say if AlphaGo saw those lines or just post-game professional analysis. No mention of Mi Yuting's s10 attachment though. Let's see what is in their release of commented games in a few weeks...
Dave Sigaty
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Uberdude
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Re: 11th Chunlan Cup
Not much directly, other than extend was good enough and result to f was good for white too with a lone black stone in a sea of white centre.ez4u wrote: What was the explanation for rejecting the double hane?
Re: 11th Chunlan Cup
Reminder !!!!!!!!!
round of 8;
Gu Zihao vs Kim Jiseok
Park Yeonghun vs Lian Xiao
Mi Yuting vs Ke Jie
Tan Xiao vs Tuo Jiaxi
round of 8 - 12/20/16
round of 4 - 12/22/16
round of 8;
Gu Zihao vs Kim Jiseok
Park Yeonghun vs Lian Xiao
Mi Yuting vs Ke Jie
Tan Xiao vs Tuo Jiaxi
round of 8 - 12/20/16
round of 4 - 12/22/16