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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 subject: Re: This 'n' that
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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 Post subject: Re: This 'n' that
Post #274 Posted: Sun May 07, 2017 9:08 am 
Judan

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This is based upon the TrueTears vs. CrazyStone 5 kyu level game. I cleaned up the position a bit.

Click Here To Show Diagram Code
[go]$$B Black to play
$$ --------------------------
$$ | . O . . . . . . . . . . .
$$ | X X O O . . . O X X . X .
$$ | . . X O O O O O O X . . .
$$ | . . X X X X O X X , . . .
$$ | . . . . . . X X . . X . .
$$ | . . . . . . . . . . . . .[/go]


This is a standard Life and Death situation. I do not recall seeing it before, but it appears in Eba's Basic Life and Death Dictionary ( http://www.h-eba.com/heba/JITEN/jiten0-1.html ).

:b1: leaped out at me, but, OC, no play may necessarily leap out. I'll leave this as a problem for now, for those who wish to treat it as such. :)

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 Post subject: Re: This 'n' that
Post #275 Posted: Sun May 07, 2017 12:32 pm 
Judan

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Click Here To Show Diagram Code
[go]$$B Black to play
$$ --------------------------
$$ | . O . C C C C . . . . . .
$$ | X X O O C C C O X X . X .
$$ | . . X O O O O O O X . . .
$$ | . . X X X X O X X , . . .
$$ | . . . . . . X X . . X . .
$$ | . . . . . . . . . . . . .[/go]


White has a 7 point room (marked) without a clear second eye. Such rooms are vulnerable.

Instead of starting with correct play, I am going to start with some mistakes, in order to explore this position.

Click Here To Show Diagram Code
[go]$$B Death in the hane?
$$ --------------------------
$$ | . O . . . . 2 1 3 . . . .
$$ | X X O O . 4 . O X X . X .
$$ | . . X O O O O O O X . . .
$$ | . . X X X X O X X , . . .
$$ | . . . . . . X X . . X . .
$$ | . . . . . . . . . . . . .[/go]


If Black plays hane-and-connect, :w4: makes two eyes.

Click Here To Show Diagram Code
[go]$$B Death in the hane? (II)
$$ --------------------------
$$ | . O 8 . 5 4 2 1 6 . . . .
$$ | X X O O 7 3 a O X X . X .
$$ | . . X O O O O O O X . . .
$$ | . . X X X X O X X , . . .
$$ | . . . . . . X X . . X . .
$$ | . . . . . . . . . . . . .[/go]


:b3: prevents the eye at “a”. :w4: threatens to make two eyes with an atari at 7. :b5: - :b7: prevent that , but then :w8: makes seki.

Click Here To Show Diagram Code
[go]$$B Death in the hane? (III)
$$ --------------------------
$$ | . O 5 7 8 4 2 1 . . . . .
$$ | X X O O 6 3 . O X X . X .
$$ | . . X O O O O O O X . . .
$$ | . . X X X X O X X , . . .
$$ | . . . . . . X X . . X . .
$$ | . . . . . . . . . . . . .[/go]

:b9: @ 5

But :b5: in this diagram kills. If :w6:, :b7: prevents a second eye. If :w6: is at 7, :b7: at 6 kills.

Click Here To Show Diagram Code
[go]$$B Death in the hane? (IV)
$$ --------------------------
$$ | . O 5 6 . 7 2 1 . . . . .
$$ | X X O O 4 3 . O X X . X .
$$ | . . X O O O O O O X . . .
$$ | . . X X X X O X X , . . .
$$ | . . . . . . X X . . X . .
$$ | . . . . . . . . . . . . .[/go]


If :w4: as in this diagram, :b5: - :b7: kills. If :w6: is at 7, :b7: at 6 kills as above.

Click Here To Show Diagram Code
[go]$$B Death in the hane? (V)
$$ --------------------------
$$ | . O 4 . . . 2 1 . . . . .
$$ | X X O O . 3 . O X X . X .
$$ | . . X O O O O O O X . . .
$$ | . . X X X X O X X , . . .
$$ | . . . . . . X X . . X . .
$$ | . . . . . . . . . . . . .[/go]


:w4: in this diagram is an excellent play. :D

Click Here To Show Diagram Code
[go]$$B Death in the hane? (VI)
$$ --------------------------
$$ | . O 4 . 6 . 2 1 5 . . . .
$$ | X X O O . 3 . O X X . X .
$$ | . . X O O O O O O X . . .
$$ | . . X X X X O X X , . . .
$$ | . . . . . . X X . . X . .
$$ | . . . . . . . . . . . . .[/go]


If :b5:, :w6: makes two eyes.

Click Here To Show Diagram Code
[go]$$B Death in the hane? (VII)
$$ --------------------------
$$ | . O 4 . 6 5 2 1 9 . . . .
$$ | X X O O 8 3 7 O X X . X .
$$ | . . X O O O O O O X . . .
$$ | . . X X X X O X X , . . .
$$ | . . . . . . X X . . X . .
$$ | . . . . . . . . . . . . .[/go]

:w10: @ 2

If :b5: in this diagram, White does best to atari with :w6:. Then after :b7: captures :w2:, :w8: captures 3 Black stones in a connect-and-die. :)

Click Here To Show Diagram Code
[go]$$B Death in the hane? (VIII)
$$ --------------------------
$$ | . O 4 . 7 5 2 1 6 . . . .
$$ | X X O O 8 3 . O X X . X .
$$ | . . X O O O O O O X . . .
$$ | . . X X X X O X X , . . .
$$ | . . . . . . X X . . X . .
$$ | . . . . . . . . . . . . .[/go]


If instead, White saves :w2:, :b7: threatens to kill. Then :w8: only gets seki.

Click Here To Show Diagram Code
[go]$$B Death in the hane? (IX)
$$ --------------------------
$$ | . O 4 9 8 5 2 1 6 . . . .
$$ | X X O O 7 3 0 O X X . X .
$$ | . . X O O O O O O X . . .
$$ | . . X X X X O X X , . . .
$$ | . . . . . . X X . . X . .
$$ | . . . . . . . . . . . . .[/go]


But if Black tries :b7:, White throws in with :w8: and makes life with oshi-tsubushi. :)

Click Here To Show Diagram Code
[go]$$B Death in the hane? (X)
$$ --------------------------
$$ | . O 4 . 5 a 2 1 6 . . . .
$$ | X X O O b 3 . O X X . X .
$$ | . . X O O O O O O X . . .
$$ | . . X X X X O X X , . . .
$$ | . . . . . . X X . . X . .
$$ | . . . . . . . . . . . . .[/go]


After :w4:, :b5: prevents a second eye, but then :w6: leaves “a” and “b” miai for seki. :)


More variations to come. :)

Edit: Made a silly oversight. :oops: Corrected.
Edit 2: Added a couple of variations. :)

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 Post subject: Re: This 'n' that
Post #276 Posted: Mon May 15, 2017 8:35 am 
Judan

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More variations, more mistakes. :)

Click Here To Show Diagram Code
[go]$$Bc Not exactly a hane
$$ --------------------------
$$ | . W 1 2 . . 4 3 . . . . .
$$ | X X O O . 5 . O X X . X .
$$ | . . X O O O O O O X . . .
$$ | . . X X X X O X X , . . .
$$ | . . . . . . X X . . X . .
$$ | . . . . . . . . . . . . .[/go]


:b1: is not a hane, because of the presence of :wc:. And at first glance it does not look right. However, it was a vital point in the previous variations.

OC, White does not immediately capture :b1:, as that leads to the easy kill shown.

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


:w2: prevents the hane, but now :b3: looks promising. If :w4:, :b5: kills.

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


:w4: can make this ko. Note that if :w8: at "a", :b9: at 4 kills.

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

:w10: @ :wc:

Curiously, :w4: makes life because of the situation in the corner. If :b9: connects at :wc:, :w10: at 9 captures 7 stones. ;)

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


Capturing the three Black stones gave White an eye. If :b1:, :w2:.

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


So after :w2:, Black can just make ko this way, with :b3:.

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


Occasionally, seki might be right. Note that if :w6: at 7, :b7: at 6 kills.

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


:w2: lives. :b3: and :b5: try to take away 2 eyes, but to no avail. If :b7: at "a", White does not even have to capture the three stones right away, as we have seen above. :)

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 Post subject: Re: This 'n' that
Post #277 Posted: Sat May 20, 2017 5:16 pm 
Judan

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The kill, at last! ;)

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


:b1: was the play the leapt out to me. “a” also kills.

Click Here To Show Diagram Code
[go]$$Bc One eye or no eye vs. eye
$$ --------------------------
$$ | . O 4 . 5 . 1 2 . . . . .
$$ | X X O O . 3 . O X X . X .
$$ | . . X O O O O O O X . . .
$$ | . . X X X X O X X , . . .
$$ | . . . . . . X X . . X . .
$$ | . . . . . . . . . . . . .[/go]


If :w2: prevents :b1: from connecting, :b3: is the vital point. Now if :w4:, :b5: is the last vital point. If White captures the Black stones, Black can make a bulky five shape to kill. If not, Black can make an eye to win the semeai. If :w4: at 5, :b5: at 4 kills.

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


:w2: takes away one dame of :b1:, but Black easily holds White to one eye.

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


:w2: takes away a dame this way. :b3: and :b5: escape, but then :w6: makes two eyes. :b5: is a mistake.

Click Here To Show Diagram Code
[go]$$Bcm5 Only one eye
$$ --------------------------
$$ | . O 1 5 . O X B 2 . . . .
$$ | X X O O 4 . O O X X . X .
$$ | . . X O O O O O O X . . .
$$ | . . X X X X O X X , . . .
$$ | . . . . . . X X . . X . .
$$ | . . . . . . . . . . . . .[/go]

:b7: @ :bc:

:b5: takes away an eye, for the kill.

After :w2: Black has a number of ways to kill. Here is another.

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


:b3: is a key point. After :w6: :b7: prevents seki and kills with a bulky five. (Yes, there are only 4 stones inside now, but Black can almost fill with a bulky five.) If :w6: at 7, :b7: at 6.

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Post #278 Posted: Sun May 21, 2017 8:55 am 
Judan

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Okigo Jizai again. :)

As I have said, I greatly admire Hattori Inshuku’s book about handicap go, Okigo Jizai. OC, go has advanced quite a bit in the past couple of centuries, but mostly in terms of opening strategy. These gains do not apply much, if at all, to high handicap games, so they remain just about as relevant today as they were back then.

The main thing I like about the book is Hattori’s spirit. It is mostly as though he shows plays that he would actually play or at least consider, himself. There is much more creativity in Okigo Jizai than in modern handicap go books, I think. There may be practical drawbacks to Hattori’s approach, in that he asks too much of Black, but he offers food for thought. :)

Another thing I like is Hattori shows how to make and use thickness. OC, in a high handicap game there are many paths to victory, but a pedestrian territory grab, even if successful, does not teach much of value in becoming a better go player. One complaint I often hear from kyu players is that they do not know how to use thickness. Hattori shows the way. OC, thickness is easier to make and use in high handicap games than in even games, but we start with baby steps. :)

I have already posted and commented in lifein19x19 on games from Okigo Jizai, but I propose to post some more in this forum, focusing on thickness and attack. :)

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Post #279 Posted: Sun May 21, 2017 12:32 pm 
Dies in gote

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Thank you for your earlier posts about Hattori's book as well - it opened my eyes to this part of the go history/culture I didn't know about. I also found his other book also available for free from the Waseda University online to be about handicap-go: http://senseis.xmp.net/?OnkoChishinGoroku
This second one seems to show lower handicap games. What is the difference in focus between these two books?

Bill Spight wrote:
Okigo Jizai again. :)
As I have said, I greatly admire Hattori Inshuku’s book about handicap go, Okigo Jizai. OC, go has advanced quite a bit in the past couple of centuries, but mostly in terms of opening strategy. These gains do not apply much, if at all, to high handicap games, so they remain just about as relevant today as they were back then.

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Post #280 Posted: Sun May 21, 2017 1:00 pm 
Judan

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alphaville wrote:
Thank you for your earlier posts about Hattori's book as well - it opened my eyes to this part of the go history/culture I didn't know about. I also found his other book also available for free from the Waseda University online to be about handicap-go: http://senseis.xmp.net/?OnkoChishinGoroku
This second one seems to show lower handicap games. What is the difference in focus between these two books?


Thanks, alphaville. :) I am not familiar with the other book. I'll check it out. :)

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