This 'n' that

Uberdude · Post by **Uberdude** » Thu Jun 11, 2020 11:42 pm

ez4u wrote:If Black does not play locally next (e.g. extends at the top), does White have a specific local continuation to exploit Black's failure to play another move at the bottom? In other words, can the bot give us a hint why the local play is rated so high?

Tenuki to top side is only 0.5% or 0.1 points worse, so I wouldn't say local play is so much better

. Normal p4 block is a white continuation from my phone bot, but it seems to like my human idea of cap when I try it so maybe that's a reason for urgency. Also it likes q7, if black jumps after that White can reasonably cap again.

John Fairbairn · Post by **John Fairbairn** » Fri Jun 12, 2020 3:52 am

If I may switch to another game, I think there are some insights to be gleaned on the above from a commentary by Ohashi Hirofumi.

In his book "Encyclopaedia of Go AI", Ohashi looks in some depth at a game in the 1st Nihon Ki-in International Championship between Iyama Yuta (White) and DeepZen (2017-03-23b if you want to look it up in GoGoD). In the position above, where the last two moves were the triangled ones, he called the one just played by Iyama an Iyama-ism. It looks rather AI-ish, doesn't it? But Leela for one doesn't like it. More to the point, Ohashi discusses this particular position under the heading "The difference between humans and go AI".

He doesn't explain that in the depth I'm sure we would all like, so I am going to try to pull together the little that he does say there with what he and other pros say elsewhere. Do keep that "I" in mind. Have a cellarful of salt handy. But Ohashi is human, too, so even for him a grain of salt may have to be reserved.

As a background point first, one of the first and most important features of AI play that Japanese pros thought they had spotted and deigned to share with us was a strong AI emphasis on inducing overconcentration in the opponent's positions very early on. In Bill's example above, this would be exemplified by moves such as White 10. Another feature was the use of very early probes. These two features often come together, and so an attempt at overconcentrating may be left off part way through.

If you look at many pro games even today, you can make sense of them to a large degree by not viewing them as fights over territory or thickness or influence but as fights over overconcentrating each other. For me the best analogy is a push-and-shove sumo bout, which of course may also start with a slap and tickle probing stage. Now, in that kind of sumo bout, within reason it's not really about who's bigger or heavier or faster. It's about who ends up first in bad shape, or in overconcentrated shape. He is the one who can be made to topple over or step out of the ring first. In go terms, bad shape punishes itself.

Obviously good sumo wrestlers (who also throw a lot of salt) learn good shape. The circled move by Iyama above can be seen as an example of that. Ohashi makes the point that this is the sort of shape that is very attractive to pros. It appears to demolish aji in the corner, and White can look forward to a large corner territory. Which is true. At least that's how it worked out in the game. But it appears that Iyama overlooked one salient point. And that blond spot may be what all pros had been missing until AI showed them the error of their ways.

Before I get on to that specific point, have a look again at the position as a whole and try to form some judgements about how it will all end up. Thoughts on what Iyama ought to have played for his last centre move and how Black now should respond would not go amiss.

What Ohashi himself notes is that Black has first occupation of two corners below, and with two stones on the fourth lines at the top, he has an advantage in speed.

What I will add is based on the final position. 235 moves were played. Iyama resigned when about 15 points behind on the board. Nothing was killed. He was just crushed. That is, overconcentrated.

White ended up with a huge upper-left corner territory - about 35 points. He also ended up making a very large investment there - about 45 stones. But in the rest of the board, Black has the upper hand (i.e. prior first occupation) and so whenever White played there, White would have to expect to take a bit of battering - which is another way of saying he would end up overconcentrated. In fact he made three extra groups, all live but at a significant cost - a total of close to 60 stones for a total of about 20 points of territory (and he also lost some stones as prisoners). That really was overconcentration. Black, meanwhile, with the upper hand, can control the development of the game and so is much more likely to end up in good shape. He is like the sumo wrestler who is genuinely heavier of faster or heavier than his opponent. That doesn't guarantee victory, but it surely helps. And one can't but help but note that it was Go Seigen's speed of foot that made his go so potent - and AI like!

Now to the specifics. Ohashi's point first: he noted that DeepZen punished White's play by playing at C. Ohashi said that this is the kind of play that characterises the strength of not just DeepZen but all AI bots. What is going on is sabaki.

If you are hamstrung by thinking of sabaki as making light, flexible shape you won't get very far in understanding what Ohashi saw. The point is, sabaki just means "coping". Ending up with light or flexible shapes may be counted as common attributes of sabaki. But so is ending up with a heavy but solid shape. That is too often overlooked. What is apparently even more overlooked, even by pros, is that another useful attribute of good sabaki is that it overconcentrates the opponent. It's pretty obvious as soon as you think about it, but that doesn't stop it being overlooked. And it worked a treat that way for Black in this game.

Keeping that in mind will perhaps allay possible surprise at the move Leela recommended for White instead of Iyama's flying bedstead. It was A. At first sight this may seem like self-inflicted overconcentration. But that's also what a honte is, is it not? The point there is that it accepts a small dose of overconcentration now to avoid a bad case of it later. In topical terms, it's a sort a vaccine. And, note well, because it eliminates sabaki for Black, it automatically makes Black weak in this area.

Moving on now to another favoured choice of Leela's: if White really does have to play in the centre, Leela suggests B. We can now see some similarity with Bill's game and Katago's "thinking".

Katago shows that it considers lots of moves in the centre, and especially in the lower-right part of the centre. But why does it plump for 15, and why did Leela prefer B?

I used to think it was all down to the bots' ability to see further ahead, and to gauge how fights in each corner would eventually coalesce at some region in the centre - invisible to us but visible to bots. I now feel ashamed of such naïve thinking.

Based partly on what Ohashi says (in connection with other games rather than the one above), I am now inclined to believe that the bots are just making shape moves in the centre, and the choice of move is simply the one that gives the shape that is least likely to end up overconcentrated.

It seems that pros have already twigged that - or something like that. The problems they are having with such high moves are down rather to understanding the timing and (maybe more important if I interpret Ohashi correctly) the order of such moves. In other words, these moves too, like the pure overconcentration-inducing moves, also have a probe element. If we extend the pugilistic analogy, these moves are like timing the changeover tag in tag wrestling. There's a lot more to it than most fans realise.

Bill Spight · Post by **Bill Spight** » Fri Jun 12, 2020 8:31 am

John, thank you for your thorough and interesting analysis.

John Fairbairn wrote:If I may switch to another game, I think there are some insights to be gleaned on the above from a commentary by Ohashi Hirofumi.

In his book "Encyclopaedia of Go AI", Ohashi looks in some depth at a game in the 1st Nihon Ki-in International Championship between Iyama Yuta (White) and DeepZen (2017-03-23b if you want to look it up in GoGoD). In the position above, where the last two moves were the triangled ones, he called the one just played by Iyama an Iyama-ism. It looks rather AI-ish, doesn't it? But Leela for one doesn't like it.

FWIW, neither does Elf.

John Fairbairn wrote:More to the point, Ohashi discusses this particular position under the heading "The difference between humans and go AI".

He doesn't explain that in the depth I'm sure we would all like, so I am going to try to pull together the little that he does say there with what he and other pros say elsewhere. Do keep that "I" in mind. Have a cellarful of salt handy. But Ohashi is human, too, so even for him a grain of salt may have to be reserved.

As a background point first, one of the first and most important features of AI play that Japanese pros thought they had spotted and deigned to share with us was a strong AI emphasis on inducing overconcentration in the opponent's positions very early on.

I noted early on that AlphaGo pincers about half as often as humans. Maybe I was the first?

Anyway, I think that this may exemplify starting from where we are. The pros thought about overconcentration, I thought about pincers.

John Fairbairn wrote:In Bill's example above, this would be exemplified by moves such as White 10. Another feature was the use of very early probes. These two features often come together, and so an attempt at overconcentrating may be left off part way through.

, the side attachment against the enclosure, goes back in human play to at least the 19th century, if not in this context.

I definitely agree about early probes. However, I have some doubts about the overconcentration hypothesis. If the purpose of the play is to induce overconcentration, why does the opponent reply? The bots are happy with both the initial play and the local response. Why accept overconcentration? Why not tenuki? We know the bots tenuki a lot. The fact that they don't indicates that the local reply does not result in overconcentration. In addition, the bots at times willingly accept what appears at first blush to be overconcentration with no prompting at all. My working hypothesis is that the bots' attitude (to anthropomorphize) to overconcentration is more like that of top players in the 19th century than that of top players in the 20th century or today. They care, but not so much.

If that's the case, then what is the purpose of plays like

, aside from possibly being probes? My working hypothesis is that the purpose is to build up some strength or influence radiating in the direction of future play. It's like the leaning part of a leaning attack without the attack.

John Fairbairn wrote:If you look at many pro games even today, you can make sense of them to a large degree by not viewing them as fights over territory or thickness or influence but as fights over overconcentrating each other. For me the best analogy is a push-and-shove sumo bout, which of course may also start with a slap and tickle probing stage. Now, in that kind of sumo bout, within reason it's not really about who's bigger or heavier or faster. It's about who ends up first in bad shape, or in overconcentrated shape. He is the one who can be made to topple over or step out of the ring first. In go terms, bad shape punishes itself.

Emphasis mine.

John Fairbairn wrote:Obviously good sumo wrestlers (who also throw a lot of salt) learn good shape. The circled move by Iyama above can be seen as an example of that. Ohashi makes the point that this is the sort of shape that is very attractive to pros. It appears to demolish aji in the corner, and White can look forward to a large corner territory. Which is true. At least that's how it worked out in the game.

It also prevents the Black tachi on the same point, which would bolster Black's pincer and start to make some territory.

John Fairbairn wrote:But it appears that Iyama overlooked one salient point. And that blond spot may be what all pros had been missing until AI showed them the error of their ways.

That's a big maybe, good buddy.

John Fairbairn wrote:What Ohashi himself notes is that Black has first occupation of two corners below, and with two stones on the fourth lines at the top, he has an advantage in speed.

Right. The problem, in my view, and in Elf's, is the high approach to the top right corner with

instead of occupying the last open corner. Elf docks

6½% by comparison.

violates my proposed last move principle for the opening: Occupy the last open corner.

Click Here To Show Diagram Code: [go]$$Wcm6 Elf's recommended variation for :w6: $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . 2 . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 1 . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . 3 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Moi, I do not find this development appealing for White. The top right enclosure looks so good, but what can I say?

OTOH, I do like DeepZen's play in response to the high approach.

Click Here To Show Diagram Code: [go]$$Wcm6 Actual game $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . . . . . . . 3 2 4 . . . | $$ | . . . O . . . . . , . . . 5 1 , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 6 , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

DeepZen secures the top right corner with sente and then occupies the last open corner. What's not to love?

John Fairbairn wrote:Now to the specifics. Ohashi's point first: he noted that DeepZen punished White's play by playing at C. Ohashi said that this is the kind of play that characterises the strength of not just DeepZen but all AI bots. What is going on is sabaki.

Well, not all AI bots. Elf does not like the hane at C. In fact, it docks it 6½% by comparison with its top choice in the next diagram.

Click Here To Show Diagram Code: [go]$$Bcm17 One space jump from the side $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O X . . . . . . . O X X . . . | $$ | . . . O . O . . . X . . . O O , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . O . . 1 . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

This is a kind of play that I am coming more and more to appreciate, a strong play near what appears to be the hot spot or focus of interest. Instead of simply strengthening Black on the top side, which is what I would do,

strengthens Black on the right side while threatening White and bolstering Black on the top side indirectly. I have to admire the play.

Click Here To Show Diagram Code: [go]$$Bcm17 Elf's variation for :b17: $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . 5 . . . . . . . | $$ | . . . . O X 4 . . . . 3 . O X X . . . | $$ | . . . O . O . . . X . . . O O , X . . | $$ | . . . . . . . . . . . 2 . . . . . . . | $$ | . . O . . . . . . . W . . 1 . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X , . . . . . , . . . . . X . . . | $$ | . . . . 6 . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

breaks the sector line and then

takes away White's potential base while making a small base for Black.

is big. Then

builds strength and threatens to connect underneath. Next,

approaches the bottom left corner.

-

refutes the high flying

(

).

John Fairbairn wrote:Keeping that in mind will perhaps allay possible surprise at the move Leela recommended for White instead of Iyama's flying bedstead. It was A. At first sight this may seem like self-inflicted overconcentration.

That's Elf's play, as well. And yes, at first glance it does seem overconcentrated. White has played 5 of his first 8 moves (4 net) in the top left corner, while his other 3 stones are under attack. But again, I am reminded of pre-20th century play by top players who knew about overconcentration.

John Fairbairn wrote:But that's also what a honte is, is it not? The point there is that it accepts a small dose of overconcentration now to avoid a bad case of it later. In topical terms, it's a sort a vaccine. And, note well, because it eliminates sabaki for Black, it automatically makes Black weak in this area.

Moving on now to another favoured choice of Leela's: if White really does have to play in the centre, Leela suggests B. We can now see some similarity with Bill's game and Katago's "thinking".

Also AlphaGo, who taught us that the three White stones in the top right do not need an extension, but can jump into the center if pincered.

John Fairbairn wrote:Katago shows that it considers lots of moves in the centre, and especially in the lower-right part of the centre. But why does it plump for 15, and why did Leela prefer B?

I used to think it was all down to the bots' ability to see further ahead, and to gauge how fights in each corner would eventually coalesce at some region in the centre - invisible to us but visible to bots. I now feel ashamed of such naïve thinking.

Based partly on what Ohashi says (in connection with other games rather than the one above), I am now inclined to believe that the bots are just making shape moves in the centre, and the choice of move is simply the one that gives the shape that is least likely to end up overconcentrated.

I think there is something there.

Bots read the whole board, OC, which is why they sometimes make local mistakes, but I have come to think that their "whole board thinking" is basically different from that of 20th century and 21st century pros. That is why, perhaps, we do not see examples of direction of play as understood in the 20th century, while we do see examples like those from the 19th century. Indeed, if the view of the bots of the center is more local than that of humans, then making shape in the center would be important, just is it is important in any other local region of the board.

Knotwilg · Post by **Knotwilg** » Fri Jun 12, 2020 8:46 am

Bill, I find the argument you offer against the hypothesis of overconcentration flawed. Whatever the concept, if the opponent bot answers it's because they judge that not answering locally is even worse. That doesn't mean they are not forced into some degree of overconcentration.

That's the whole point of sente, regardless of the underlying concept: you play a move because you think the opponent should answer locally and you think it gives you some benefit. When the opponent answers, that can still be his best move. And that in turn doesn't mean the sente was wrong.

Many concepts would lose their meaning, like "shape", if refusing to be coerced into it, like "bad shape", were always better than allowing for it.

Go concepts exist because the game isn't solved. When the game is solved, there is only the concept of "best move".

RobertJasiek · Post by **RobertJasiek** » Fri Jun 12, 2020 8:57 am

A solved game need not lose concepts, which might classify correct plays of same kinds.

Bill Spight · Post by **Bill Spight** » Fri Jun 12, 2020 9:11 am

Knotwilg wrote:Bill, I find the argument you offer against the hypothesis of overconcentration flawed. Whatever the concept, if the opponent bot answers it's because they judge that not answering locally is even worse. That doesn't mean they are not forced into some degree of overconcentration.

Well, to quote, more or less, from ancient memory, Lasker's Chess Primer, "We have not made a mistake. There must be a good reply." If a player can be forced into overconcentration, it must be because of a previous error. Now, in this case, arguably the previous error is the keima enclosure instead of a large knight's enclosure or a two space high enclosure. So you make a good point for

in the earlier diagram. However, forcing overconcentration cannot be a general strategy unless your opponent consistently makes the right kind of errors.

That's the whole point of sente, regardless of the underlying concept: you play a move because you think the opponent should answer locally and you think it gives you some benefit. When the opponent answers, that can still be his best move. And that in turn doesn't mean the sente was wrong.

Sure. But we don't say that the reply to the sente gets a bad result, either, i.e., kikasare. Fair is fair.

Many concepts would lose their meaning, like "shape", if refusing to be coerced into it, like "bad shape", were always better than allowing for it.

Well, yes, I love to give my opponents bad shape. But, again, that depends upon their having made a previous error that I can recognize. It doesn't happen that often.

Edit: While forcing the opponent to make bad shape cannot be a general strategy, at least on the dan level, preventing the opponent from making good shape can be. It seems to me that the bots' top choices are often those that, while not forcing bad shape or overconcentration on the opponent, prevent the opponent from making good shape. When I note a shape play by a bot, it is usually of that sort, rather than making good shape itself.

Bill Spight · Post by **Bill Spight** » Fri Jun 12, 2020 9:29 am

And on the topic of high flying AI moves, here is another one.

Click Here To Show Diagram Code: [go]$$Wcm16 Elf's variation for :w16: $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O X 1 . . . . . . O X X . . . | $$ | . . . O . O . . . X . . . O O , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . 2 . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Like LZ, Elf likes the strong

. But then it recommends the high flying large knight's jump.

Beautiful, isn't it?

John Fairbairn · Post by **John Fairbairn** » Fri Jun 12, 2020 10:37 am

Bill, I find the argument you offer against the hypothesis of overconcentration flawed. Whatever the concept, if the opponent bot answers it's because they judge that not answering locally is even worse. That doesn't mean they are not forced into some degree of overconcentration.

That's the whole point of sente, regardless of the underlying concept: you play a move because you think the opponent should answer locally and you think it gives you some benefit. When the opponent answers, that can still be his best move. And that in turn doesn't mean the sente was wrong.

I was going to comment on Bill's point, too, though not to counter it, at least not in such a direct way. In fact, in a quite diffident way. If we call these negotiations "overconcentration fights" for want of an existing term, what I have noticed about them is the peculiar way they stop, start and jerk about. It is not a smooth process, and my guess is that what we are seeing is, here too, a series of moves predicated on getting them in the right order, or well timed in other ways. I speculate that what may be happening on the grand scale is that time is becoming a much bigger element in go then ever before. Up to now it has been dominated by shape, in all its guises.

A further way of characterising it that often comes to me (because it makes such a strong impression on me when I see it) is that it's like the difference between Rembrandt and Picasso. Or between classical ballet and modern dance. In short, there's an abstract jerkiness.

Kirby · Post by **Kirby** » Fri Jun 12, 2020 11:14 am

Bill Spight wrote:And on the topic of high flying AI moves, here is another one.

$$Wcm16
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . O X 1 . . . . . . O X X . . . |
$$ | . . . O . O . . . X . . . O O , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . 2 . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
Click Here To Show Diagram Code
[go]$$Wcm16 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O X 1 . . . . . . O X X . . . | $$ | . . . O . O . . . X . . . O O , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . 2 . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]
Like LZ, Elf likes the strong . But then it recommends the high flying large knight's jump. Beautiful, isn't it?

I like that move. When I look at the position with whatever version of KataGo I have, that's one of the moves katago explores, too. Then it starts to favor the small knight's move:

Click Here To Show Diagram Code: [go]$$Wcm16 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O X 1 . . . . . . O X X . . . | $$ | . . . O . O . . . X . . . O O , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . 2 . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

and then after a little while (I stopped watching after 10k playouts), it recommends this:

Click Here To Show Diagram Code: [go]$$Wcm16 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O X 1 . . . . . . O X X . . . | $$ | . . . O . O . . . X . . . O O , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . 2 . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

The last one kind of makes sense to me - it establishes a good position on the right. So I looked at some of the follow-ups for the large knight's you posted, along with the small knight's move. In both cases, it seemed to think that white would jump out, and then black could tenuki and enclose the bottom left:

Click Here To Show Diagram Code: [go]$$Wcm16 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O X 1 . . . . . . O X X . . . | $$ | . . . O . O . . . X . . . O O , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . 2 . . 3 . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X , 4 . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

If I actually play out the large knight's move, it adjusts a bit, and then white gets to play in the bottom left first:

Click Here To Show Diagram Code: [go]$$Wcm16 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O X 1 . . . . 4 . O X X . . . | $$ | . . . O . O . . . X 6 5 . O O , X . . | $$ | . . . . . . . . . . . 7 . . . . . . . | $$ | . . O . . . . . . 8 . . . . . X . . . | $$ | . . . . . . . . . . 2 . 3 . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X , . . . . . , . . . . . X . . . | $$ | . . . . 9 . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

White the smaller knight's move, even after I play it, I guess white doesn't have the same kind of forcing move against it, so it still recommends for white to jump out:

Click Here To Show Diagram Code: [go]$$Wcm16 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O X 1 . . . . . . O X X . . . | $$ | . . . O . O . . . X . . . O O , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . 2 . . . . X . . . | $$ | . . . . . . . . . . . . . 3 . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

And then black can play in the bottom left again.

My thought here is that the bottom left approach/enclosure is somewhat big, so one possible idea for black is to strengthen his single stone on top a bit, and enclose the bottom left.

If that's true, then why not just enclose the bottom left first? If I try that...

Click Here To Show Diagram Code: [go]$$Wcm16 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O X 1 . . . . . . O X X . . . | $$ | . . . O . O . . . X . . . O O , X . . | $$ | . . . . . . . . . . 3 . . . . . . . . | $$ | . . O . . . . . . . . . . . . X . . . | $$ | . . C . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X , 2 . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

KataGo doesn't even recommend that black responds to the 5th line shoulder hit, instead, favoring the tenuki at the marked intersection on the left. I suppose white is strong in the area, so there may be some disadvantage to continuing there....

So maybe black aims to get a group that can't be strongly attacked, then move to the big area in the bottom left quickly?

Bill Spight · Post by **Bill Spight** » Fri Jun 12, 2020 11:38 am

John Fairbairn wrote:If we call these negotiations "overconcentration fights" for want of an existing term, what I have noticed about them is the peculiar way they stop, start and jerk about. It is not a smooth process, and my guess is that what we are seeing is, here too, a series of moves predicated on getting them in the right order, or well timed in other ways. I speculate that what may be happening on the grand scale is that time is becoming a much bigger element in go then ever before. Up to now it has been dominated by shape, in all its guises.

Interesting idea.

I recall the Elf team saying that it learned to play the endgame first, which makes sense in unsupervised training. And the endgame, once the board is divided into independent regions, typically makes a move or two in one region, then switches to another region where the play has become more important, and so on. What if zero bots view the board, not as fully independent regions, but as quasi-independent regions? Then play would develop in a similar fashion, a few plays here, a few plays there, and so on and so forth. Play might start in the corners, and then it might take a while for the sides to become important. In such play the corners might appear to us humans, who are not used to such a way of playing, to become a bit overconcentrated before play widened to the sides and center.

John Fairbairn · Post by **John Fairbairn** » Fri Jun 12, 2020 11:41 am

KataGo doesn't even recommend that black responds to the 5th line shoulder hit, instead, favoring the tenuki at the marked intersection on the left.

This is a conventional way of describing the situation which maybe close to 100% of us would use.

But it has consequences. If a guy hits us we hit back, right? Or if he's too strong we run away. Whatever we do, we respond. That's implied in a "hit".

Bots don't have those hang-ups.

Can I suggest you might find a vastly different way of seeing these situations if you don't say "shoulder hit" but "shoulder probe"? And that that may give you more of bot's eye view.

After all, in real life we "respond" quite differently to a hit on the shoulder and a tap on the shoulder. Would we respond at all to a "look" at our shoulder? I suspect our reaction would be: "What's he up to?" And if he's a Minneapolis cop, we think: "Tenuki, fast!"

ez4u · Post by **ez4u** » Fri Jun 12, 2020 7:00 pm

I realize that the discussion of this position has finished but I only today have had time to post some interesting insights from running katago on the earlier position.

All of the following is based on calculations using the katago 20-block (my hardware limitations) with Japanese rules and analysisWideRootNoise = 0.03 (my new standard = moderate diversity in search). In this case I also set komi to zero.

Bill Spight wrote:The four enclosure position is from a 19th century game, but could arise today. Black has fallen behind, because of the two tight enclosures.

In the game Black played at a, the traditional extension between facing enclosures, but the shoulder play (b)is modern AI style...

It turns out that the 20b calculates blue as the slightly wider extension at c below. This is true at 10K playouts and persists at 200K (the limit of my patience).

Both b and a are nearly as highly regarded. That is not the interesting point. IMHO the interesting lesson from katago is how we should think about playing against the small knight enclosure.

Click Here To Show Diagram Code: [go]$$Bcm9 A classic fuseki $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . X . . . . | $$ | . . . , . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , a . . | $$ | . . . . . . . . . . . . . . . . c . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . . . . . b . , O . . | $$ | . . . X . . . . . . . . . . O . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Most of us (and virtually all of us who took up the game before alphago?) have seen a diagram like the following in this or that fuseki book. The explanation is that

allows Black to build on a larger scale than White.

Click Here To Show Diagram Code: [go]$$Bcm9 A classic fuseki $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . X . . . . | $$ | . . . , . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . 3 , 1 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . 4 . 2 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . . . . . . . , O . . | $$ | . . . X . . . . . . . . . . O . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Katago sees it a little differently. Whether Black extends all the way to R9 below or holds back to R10 as above (with White responding at either R8 or R7), Black answers a White extension by immediately attaching at O3. GoGoD turns up no examples of this pattern among us mere mortals.

Click Here To Show Diagram Code: [go]$$Bcm9 Katago will attach next $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . X . . . . | $$ | . . . , . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , a . . | $$ | . . . . . . . . . . . . . . . . 1 . . | $$ | . . . . . . . . . . . . . . . . b . . | $$ | . . . . . . . . . . . . . . . . 2 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . . . . . . 7 , O . . | $$ | . . . X . . . . . . 9 . 5 3 O 8 . . . | $$ | . . . . . . . . . . . . 6 4 . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Katago calculates that White does best to respond to the original extension. The reason is another attachment. In lines where White plays elsewhere, for example extending at the top, katago favors the immediate attachment at R5 below.

Click Here To Show Diagram Code: [go]$$Bcm9 Katago will attach next here too! $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . X . . . . | $$ | . . . , . . . . . 2 . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , a . . | $$ | . . . . . . . . . . . . . . . . 1 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . 3 . . | $$ | . . . , . . . . . . . . . . . , O . . | $$ | . . . X . . . . . . . . . . O . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

I was excited by this "idea" that the power of the initial extension comes from the ability to exploit the tightness of the small knight enclosure by attaching on one side or the other. It is something not on my personal radar screen at all, up to now. The extensions have been around for centuries as the answer to "what's the next move" fuseki problems. But we may have to rewrite some of those "read the next 3 moves" problems.

Bill Spight · Post by **Bill Spight** » Fri Jun 12, 2020 8:22 pm

Thanks, Dave! That's great stuff. Verrrrry interesting.

BTW, the game was 1844-10-09a, between Honinbo Shuwa (W) and Yasui Sanchi IX, both 7 dan.

Bill Spight · Post by **Bill Spight** » Fri Jun 12, 2020 8:41 pm

Now for something easy.

Click Here To Show Diagram Code: [go]$$B Evaluate $$ ---------------- $$ . O X X X X . . . $$ . O C C C X X . . $$ . O B B B C X X . $$ . O O O O B O X . $$ . . . . O O O X . $$ . . . . . . . . .[/go]

What's the territorial count for the marked points and stones?

How much does a play gain?

Enjoy!

Bill Spight · Post by **Bill Spight** » Sat Jun 13, 2020 9:21 am

Click Here To Show Diagram Code: [go]$$B Evaluate $$ ---------------- $$ . O X X X X . . . $$ . O C C C X X . . $$ . O B B B C X X . $$ . O O O O B O X . $$ . . . . O O O X . $$ . . . . . . . . .[/go]

What's the territorial count for the marked points and stones?

How much does a play gain?

---------------------------

This is easy, so I'll just hide the solution without waiting for anyone to respond.

OK, here goes.

A simple corridor with a wrinkle at the end.

Click Here To Show Diagram Code: [go]$$B Black first $$ ---------------- $$ . O X X X X . . . $$ . O 1 C C X X . . $$ . O X X X . X X . $$ . O O O O B O X . $$ . . . . O O O X . $$ . . . . . . . . .[/go]

Black gets 2 pts. for the marked points and White gets ⅓ pt. for the marked ko stone.

Result: 1⅔ pts.

Click Here To Show Diagram Code: [go]$$W White first, Black reply $$ ---------------- $$ . O X X X X . . . $$ . O 1 2 C X X . . $$ . O X X X . X X . $$ . O O O O B O X . $$ . . . . O O O X . $$ . . . . . . . . .[/go]

Result: ⅔ pt.

Click Here To Show Diagram Code: [go]$$W White - White - Black $$ ---------------- $$ . O X X X X . . . $$ . O 1 3 . X X . . $$ . O X X X 4 X X . $$ . O O O O X O X . $$ . . . . O O O X . $$ . . . . . . . . .[/go]

Result: 0

Click Here To Show Diagram Code: [go]$$W White - White - White - Black $$ ---------------- $$ . O X X X X . . . $$ . O 1 3 6 X X . . $$ . O X X X 5 X X . $$ . O O O O B O X . $$ . . . . O O O X . $$ . . . . . . . . .[/go]

White gets 1 pt. for the captured

stone, Black gets ⅓ pt. for the

stone.
Result: -⅔ pt.

is sente, OC, so -⅔ pt. is the territorial count after

. And that means that

is a reverse sente gaining ⅔ pt.

And that means, with the result after

, that the territorial count after

is (⅔ - ⅔)/2 = 0, with a play by either side gaining ⅔ pt. The position after

is ambiguous between sente and gote, as the local temperature remains the same after

.

And that means, with the result after

, that the territorial count of the original position is (1⅔ + 0)/2 = ⅚ pt., with a play by either player gaining ⅚ pt.

Life In 19x19

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Re: This 'n' that

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