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 Post subject: Re: This 'n' that
Post #261 Posted: Mon Oct 31, 2016 5:59 pm 
Gosei

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I have not done a study of that base, but it still occurs today, although not very frequently. We have seen it in these very ancient games when a player played on the 3-11 point with the 3-8 point as a miai point to make a base. In the early modern era players often made the base with no provocation at all. OC, making this base would usually be slow by today's standards.


I have to disagree on a couple of points.

Not sure what you mean exactly by early modern era, but whatever the cut-off, until the late 20th century players made many moves in consideration of there being no komi, so they may not have been making this shape gratuitously.

More important, this shape is nowhere near as rare as you seem to think today. Taking a generous space, with a third-line two-space extension centred inside an otherwise empty 10x5 rectangle of points based on the sides (to attenuate the charge of provocation from nearby stones), roughly 80% of well over 1,000 games in the GoGoD database that have this pattern can be classed as modern, taking as an arbitrary cut-off point the advent of Go Seigen. Even if you want to restrict it to very recent years it is still very common, and appears without any obvious bias in all the major pro countries and with the usual cast of stars.

If you are counting early Edo as "early modern", with one exception the shape does not appear before 1620 (Dosaku) and is not specially common thereafter in early Japan. It is the Chinese who played it most then.

If you make the rectangle 8x5, it's ten times more common (almost 15% of all games) and even more so in modern play. Making the cut-off date here equally arbitrary at 1980, 75% of cases are in modern games (Sansa still gets just one).

Not every case can be classed as a base pure and simple, but plenty can (most? - over 90% of cases occur in the first 50 moves), and of course even extensions from a moyo can be cut off and have to fend for themselves.

It's more the third line and pincer width that differentiate the ancients from the moderns rather than two-space bases (see also Fukui Masaaki on this topic).

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 Post subject: Re: This 'n' that
Post #262 Posted: Mon Oct 31, 2016 6:32 pm 
Judan

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John Fairbairn wrote:
Quote:
I have not done a study of that base, but it still occurs today, although not very frequently. We have seen it in these very ancient games when a player played on the 3-11 point with the 3-8 point as a miai point to make a base. In the early modern era players often made the base with no provocation at all. OC, making this base would usually be slow by today's standards.


I have to disagree on a couple of points.

Not sure what you mean exactly by early modern era, but whatever the cut-off, until the late 20th century players made many moves in consideration of there being no komi, so they may not have been making this shape gratuitously.

More important, this shape is nowhere near as rare as you seem to think today. Taking a generous space, with a third-line two-space extension centred inside an otherwise empty 10x5 rectangle of points based on the sides (to attenuate the charge of provocation from nearby stones), roughly 80% of well over 1,000 games in the GoGoD database that have this pattern can be classed as modern, taking as an arbitrary cut-off point the advent of Go Seigen.


Thanks, John. :) I was talking specifically about the 3-8, 3-11 base, while you seem to be talking about bases on the side in general. I could still be mistaken about its incidence, however.

It shows up with setup stones in exchanges such as this.

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


I think that this sequence would be quite rare these days. :)

Edit: In fact, given that the idea of a base is fundamental opening knowledge, it would be surprising if they were not common. :)

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 Post subject: Re: This 'n' that
Post #263 Posted: Mon Oct 31, 2016 7:21 pm 
Gosei

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Bill, that precise shape only occurs 11 times, all Chinese, all very ancient, and at a time when group tax still applied. The importance of connectivity therefore might have been more important than its value as a base.

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 Post subject: Re: This 'n' that
Post #264 Posted: Mon Oct 31, 2016 8:35 pm 
Judan

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John Fairbairn wrote:
Bill, that precise shape only occurs 11 times, all Chinese, all very ancient, and at a time when group tax still applied. The importance of connectivity therefore might have been more important than its value as a base.


Thanks, John. :) Good point about the group tax.

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 Post subject: Re: This 'n' that
Post #265 Posted: Mon Oct 31, 2016 9:21 pm 
Judan

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In another game the 3-8, 3-11 base occurs twice: The famous "Four Immortal meet in Chengdu" game, dated 1094. :)

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


:w4: is a wedge with miai to make a base.

Click Here To Show Diagram Code
[go]$$Bcm19 Another wedge
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 2 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 1 . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . 3 . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . O X . . . . . . . . . . . . O . . |
$$ | . . O X . X . . . . . . . . . . . . . |
$$ | . . . O X . . . . , . . . . . X . . . |
$$ | . . O . O X . O . . O . X . . . . . . |
$$ | . . . . O X . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Ditto for :b19:. :)

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 Post subject: Re: This 'n' that
Post #266 Posted: Tue Nov 01, 2016 11:20 am 
Judan

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The 3-8, 3-11 base has never disappeared, but it may be making a resurgence, along with the 3-11 wedge, as players emphasize the sides more. Here is one example, dated Feb. 28, 2013, among several in recent years. :)

Click Here To Show Diagram Code
[go]$$Bc Takemiya (W) - Yuki Satoshi
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 4 . . . . . , . . . . 5 , 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 8 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . 6 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 7 . . |
$$ | . . . 2 . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . 3 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


White plays the wedge, :w6:, allowing Black to make a second enclosure with :b7:. Then :w8: makes a base.

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 Post subject: Re: This 'n' that
Post #267 Posted: Tue Nov 01, 2016 5:06 pm 
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Click Here To Show Diagram Code
[go]$$Bc Takemiya (W) - Yuki Satoshi
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 4 . . . . . , . . . . 5 , 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 8 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . 6 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 7 . . |
$$ | . . . 2 . . . . . a . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . 3 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


But wouldn't 3, 7 and a be good shape for Black? White playing the wedge at :w6: basically lets Black get that shape.

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 Post subject: Re: This 'n' that
Post #268 Posted: Tue Nov 01, 2016 6:04 pm 
Judan

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Fedya wrote:
Click Here To Show Diagram Code
[go]$$Bc Takemiya (W) - Yuki Satoshi
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 4 . . . . . , . . . . 5 , 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 8 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . 6 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 7 . . |
$$ | . . . 2 . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . 3 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


But wouldn't 3, 7 and a be good shape for Black? White playing the wedge at :w6: basically lets Black get that shape.


Yup. :) That's why :w6: wasn't played much for a long time. But it seems to be coming back into style.

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 Post subject: Re: This 'n' that
Post #269 Posted: Wed Nov 02, 2016 3:53 am 
Gosei

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I may be misunderstanding where you are going with this, Bill, but again I don't think the figures are bearing out what you are saying about commonness, modernness or resurgences.

In the specific fuseki you show, the R9 wedge (your 3-11) is rare - just 5 cases and all since 2000. Overwhelmingly, in that position White does not wedge but plays a kakari.

If you strip out the left-side White stones, the right side is still not hugely common - about 500 cases ever, and the wedge still appears only in 10% of cases.

The Black shimari has some effect. The Black shape with small knight's move shimari is some 8 times more common, but then the incidence of the wedge drops to about 5%. I assume we can infer that White is hoping to do something a bit more specific against the high shimari than just making a base. This seems supported by the fact that the incidence of White R9 against a Black shimari with a large knight's move is also very close to that with the small knight's move. Agreed, though, that the more specific bit must include something to do with stressing the side.

You mention Takagawa a lot in this connection. My memory on this is vague but I think I too can recall him talking about the wedge a lot - but only in theory. If so, I wonder whether you have got a wrong idea of frequency from that and are talking more about examples in captivity rather than in the wild.

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 Post subject: Re: This 'n' that
Post #270 Posted: Thu Nov 03, 2016 5:31 pm 
Judan

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I haven't forgotten you, John. It's just that I anticipate making an extended reply.

One thing quickly. IMO, the idea of a base is one of the fundamentals of the opening. My reference to Takagawa is in support of that. :)

Another thing, the 3-8, 3-11 base is a minor theme. I noticed it in 17th century openings, and was surprised to find it in very ancient openings, as well. :)

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 Post subject: Re: This 'n' that
Post #271 Posted: Fri Nov 04, 2016 8:00 am 
Judan

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Continuing piecemeal:

For quite some time I have had the impression that currently the pros are emphasizing the sides in the opening more than they did in the 20th century (after the New Fuseki period). OC, that is obvious in the Chinese fuseki and mini-Chinese, as well as the Kobayashi fuseki, in which a side extension is played before making an enclosure. But it has seemed to me that the pros have recently gone even further. In my exploration of the side base in the opening I had not planned to look at recent games, as I think that, even if the advanced thinking behind the plays is different these days, the fundamentals have not changed since the 17th or 18th century. I may change my mind as I explore further. :)

Gotta run now.

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Post #272 Posted: Mon Apr 24, 2017 7:18 am 
Judan

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Something new. :)

TrueTears recently posted an interesting game against CrazyStone DL with the 5 kyu setting on Android. ( forum/viewtopic.php?f=4&t=14181 ) :)

One question that it provokes is whether Black has a ko threat in the top left corner for the 1/3 pt. ko (marked).

Click Here To Show Diagram Code
[go]$$Bc Black ko threat in top left corner?
$$ ---------------------------------------
$$ | . . . . . O O X . . . X O O . . . . . |
$$ | . . . O O O X X . . . X X O O . . . . |
$$ | . . . O X X . . X . . . . X O O . O . |
$$ | . . . O O X . . . , . . X X X , O . O |
$$ | . . . O . W X . X X X X O O X X X O . |
$$ | O O O O O X . O X O X X X O O O O X . |
$$ | O X O X X . X O X O O X O O . O X X . |
$$ | X X X X X X X O X O . O . O X O X O X |
$$ | . . X O O X O X X O O . O X . X X O . |
$$ | . X X O O O O O O X O . O X X , X O O |
$$ | X X O X X X X . X X X O O O O X X X O |
$$ | X O O X X X X X X . O O X X X X O O . |
$$ | O . O O X O X O X O . O X . . X O . O |
$$ | . O O X O O O O O O . O O X X O O . . |
$$ | . . O X X . O O X O O X X . X O . . . |
$$ | . O O X . X O X X X O O X . . X O O . |
$$ | O O X X . X X X X O O X X X X X O . . |
$$ | O X O . . . . X X X O O X O O O . . . |
$$ | X X X X . . . . X O O . O . . . . . . |
$$ ---------------------------------------[/go]


What do you think?

I'll give my thoughts tomorrow. :)

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 Post subject: Re: This 'n' that
Post #273 Posted: Wed Apr 26, 2017 12:07 am 
Judan

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I think that Black will often have a ko threat in the top left corner, but there are some wrinkles.

Click Here To Show Diagram Code
[go]$$Bc Ko threat?
$$ -------------------
$$ | . . . . . O O X .
$$ | . 1 . O O O X X .
$$ | . . . O X X . . X
$$ | . 3 . O O X . . .
$$ | . . . O 2 O X . X
$$ | O O O O O X . O X
$$ | O X O X X . X O X
$$ | X X X X X X X O X
$$ | . . X O O X O X X[/go]


Let Black play :b1: as a ko threat. Now if :w2: fills the ko, Black jumps to :b3:. This looks a lot like seki.

However . . .

Click Here To Show Diagram Code
[go]$$Wcm4 Seki?
$$ -------------------
$$ | . 2 . . . O O X .
$$ | 6 X 1 O O O X X .
$$ | 4 3 5 O X X . . X
$$ | 9 X 8 O O X . . .
$$ | 0 7 . O O O X . X
$$ | O O O O O X . O X
$$ | O X O X X . X O X
$$ | X X X X X X X O X
$$ | . . X O O X O X X[/go]


:w4: secures the White eye and threatens to take away the Black eye. :b5: - :b9: secure the Black eye in the corner. But now :w10: threatens to make a second eye for White. :b11: prevents that, but now White plays a throw-in at :w12:.

Click Here To Show Diagram Code
[go]$$Wcm14 No Seki
$$ -------------------
$$ | . X 3 . . O O X .
$$ | X X O O O O X X .
$$ | X O O O X X . . X
$$ | 2 X X O O X . . .
$$ | X O 1 O O O X . X
$$ | O O O O O X . O X
$$ | O X O X X . X O X
$$ | X X X X X X X O X
$$ | . . X O O X O X X[/go]


White wins the semeai, so that line does not work for Black.

Click Here To Show Diagram Code
[go]$$Bcm5 Seki?
$$ -------------------
$$ | 3 2 1 7 . O O X .
$$ | . X O O O O X X .
$$ | 5 4 6 O X X . . X
$$ | . X . O O X . . .
$$ | . . . O O O X . X
$$ | O O O O O X . O X
$$ | O X O X X . X O X
$$ | X X X X X X X O X
$$ | . . X O O X O X X[/go]


Suppose that Black tries the hane, :b5:. :w6: throws in and then :w8: - :w10: prevent an eye for Black. But then :b11: not only takes away White’s eye, it prevents the throw-in trick because of damezumari.

Click Here To Show Diagram Code
[go]$$Wcm12 Ko
$$ -------------------
$$ | X . X X . O O X .
$$ | . X O O O O X X .
$$ | X O O O X X . . X
$$ | 1 X 4 O O X . . .
$$ | 2 3 . O O O X . X
$$ | O O O O O X . O X
$$ | O X O X X . X O X
$$ | X X X X X X X O X
$$ | . . X O O X O X X[/go]

:w16: takes ko.

But White has a slightly different throw-in trick, which makes ko. And White takes the ko first, so Black still has to find a ko threat.

But wait! There’s more! White can do better. :)

Click Here To Show Diagram Code
[go]$$Wcm8 Another ko
$$ -------------------
$$ | X 3 X 1 . O O X .
$$ | . X O O O O X X .
$$ | . 2 . O X X . . X
$$ | . X . O O X . . .
$$ | . . . O O O X . X
$$ | O O O O O X . O X
$$ | O X O X X . X O X
$$ | X X X X X X X O X
$$ | . . X O O X O X X[/go]


:w8: makes ko and an eye at the same time. :) In addition . . .

Click Here To Show Diagram Code
[go]$$Wc Ko threats
$$ -------------------
$$ | X . X O . O O X .
$$ | . X O O O O X X .
$$ | 6 X . O X X 4 . X
$$ | 5 X 2 O O X 3 . .
$$ | . 1 . O O O X a X
$$ | O O O O O X . O X
$$ | O X O X X . X O X
$$ | X X X X X X X O X
$$ | . . X O O X O X X[/go]


White has three local threats. :w1: threatens to make a second eye, :w3: threatens to capture three Black stones for a second eye, and :w5: threatens to take away Black’s eye. White has a threat at “a”, but it is not large enough to make up for letting Black live in the corner.

Does Black really have a ko threat in this corner? If White fills the 1/3 point ko, he trades it for a larger ko, but not one which Black takes first, one which White takes first, instead. Furthermore, White has three local ko threats. Black needs four extra threats just to keep up! :shock:

That is true. But this is a picnic ko for Black. White has to win it, or get sufficient compensation in exchange. Otherwise White takes a loss by winning the 1/3 point ko. But Black can afford to lose the ko, as long as she gets enough in exchange. And all Black needs to get enough is enough to afford to lose the original 1/3 point ko. In effect, Black is fighting the original, small ko while White is fighting the large ko. White may have ko threats that would be effective in the original ko fight but are too small to win the large ko. Also, Black may have losing ko threats that she could not afford to play against the original, small ko, but which she can afford to play against the large ko. :)

So whether this is a ko threat for the 1/3 point ko is a big maybe. :D

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