It is currently Mon Mar 18, 2024 10:30 pm

All times are UTC - 8 hours [ DST ]




Post new topic Reply to topic  [ 20 posts ] 
Author Message
Offline
 Post subject: Hoen Shinpo--Are historical handicap openings still good?
Post #1 Posted: Wed Aug 11, 2021 10:17 am 
Lives in sente
User avatar

Posts: 714
Liked others: 109
Was liked: 138
Rank: Shokyu
Universal go server handle: CDavis7M
I was on the search for commentary on Shuwa's games (English, Japanese, or otherwise) besides those in Invincible and Appreciating Famous Games and I discovered Fairbairn's translation of Hoen Shinpo written by Honinbo Shuho. The second half of the book contains 10 of Shuho's games against Shuwa and 10 games against Shusaku.

The first half of the book contains short commentary on 4, 3, and 2-stone openings (50 to 60 moves). Instead of jumping straight to Shuwa's games I started playing through the 4-stone openings and I am enjoying them. Given Shuho's brevity and lack of rationale, I am following Fairbairn's suggestion to understand for myself why Shuho bothered to comment on a particular play. But having gone through several 4-stone openings, I am wondering whether the plays and commentary are even relevant today?

For example, I often see black playing the 4th-line attachment against the keima kakari (attach and extend variation): https://senseis.xmp.net/?44PointLowApproachAttach. Usually in response to a double kakari (which was allowed) but sometimes immediately. Sensei's states that AI does not favor this joseki. I also see the olde ogeima from 4-4 shimari/response. But does this even matter in a handicap game? Is this not a good joseki for a "beginner" anymore? Or is it still fine to use in handicap matches? And some of Shuho's commentary goes beyond what I would consider as the opening.

What do you think? Is it worth my time reviewing historical handicap openings or has AI changed the handicap openings as well?

By the way, I also own "Handicap Go" (Yoshiaki & Bozulich, 1982), which might be considered historical at this point.


========================================

Image

Shuho says that black's trade taking the middle point on the upper side for white's second kakari on the right-side is "very good" for black. So, better than the "good" that Shuho typically uses.

Shuho say's that ignoring White's kakari against the lower-right corner to play the pincer on the center of the left-side against the white group in the upper-left is "one idea." Hm...


Last edited by CDavis7M on Wed Aug 11, 2021 10:37 am, edited 1 time in total.
Top
 Profile  
 
Online
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #2 Posted: Wed Aug 11, 2021 10:29 am 
Gosei
User avatar

Posts: 1747
Liked others: 176
Was liked: 488
I think that unless you are a professional, any joseki is playable. Change the rules slightly and Katago will play openings very differently: https://lifein19x19.com/viewtopic.php?f=18&t=18031

Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #3 Posted: Wed Aug 11, 2021 1:10 pm 
Lives in sente

Posts: 1037
Liked others: 0
Was liked: 180
Perhaps more importantly, the concept of "joseki" (fair/optimum division of the spoils) is in a vacuum, other stones not on the board. But there will be other stones on the board. In a vacuum, there might be several choices of joseki.But given the presence of other stones on the board, some of them may no longer be "joseki"

THAT is going to be of much more importance (the correct selection of joseki) than any slight improvement modern AI might make in the theoretically best lines of some.

Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #4 Posted: Wed Aug 11, 2021 11:55 pm 
Lives in sente

Posts: 896
Liked others: 22
Was liked: 168
Rank: panda 5 dan
IGS: kvasir
CDavis7M wrote:
What do you think? Is it worth my time reviewing historical handicap openings or has AI changed the handicap openings as well?


If you don't study handicap games, then what else would you study? You have this book, it sounds interesting and you are interested. It is worth it :tmbup:

In handicap games (and really to some extent in every game) the perception of what is normal, what is too easy and what is too complicated plays a big role, which means that a 4 stone handicap game between 1d and 4k will not be same as between 7d and 3d. It is not so relevant if someone else would play completely differently in the same situation, as long as the games demonstrate good fundamentals and a reasonable approach to the positions that come up.

In the end it is about what you are willing to study, and when you find something that is interesting it is often motivating and you end up studying and playing more.

Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #5 Posted: Thu Aug 12, 2021 1:33 am 
Oza

Posts: 3644
Liked others: 20
Was liked: 4620
I think this thread illustrates much of what is wrong with amateur go, and western go in particular because we start with a much more rickety structure.

The query starts off with reference to a book of openings. It descends instantly to a discussion of joseki, with no mention of fuseki. It's many years since I translated the book, but my memory of it is that it doesn't even mention joseki or fuseki.

It is a collection of model plays. In old go this was a much esteemed way of studying, in China especially. There, top players would present whole collections of self-play "games", usually up to about move 70 or 80. They saw the merits of self-play centuries before AlphaGo, and applied it to both even games and handicap games.

The concept was relatively "new" to Japan in Shuho's day, and he referred to new "ways", not new (or old, or good, or bad) josekis or fusekis. It was model go (hoen, over the whole board, not joseki or fuseki). The key word is 法 (way), which is still used in Chinese to mean 'take as a model'. There are similar meanings in Japanese. The reader's task is to think about why the moves serve as a model, and that can only be done by considering the whole board.

There are signs in various parks near me that, on large notices next to the ponds, ask visitors not to feed bread to the ducks as it harms them (proper duck food is available in the nearby cafes for pennies). But every day scores of people toss lumps of bread into the water. Go pros similarly toss joseki bread to amateurs, who gobble it up and wonder why they feel queasy afterwards. It may be telling that the Japanese for a sucker is kamo - a duck.


This post by John Fairbairn was liked by: CDavis7M
Top
 Profile  
 
Online
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #6 Posted: Thu Aug 12, 2021 5:16 am 
Gosei
User avatar

Posts: 1747
Liked others: 176
Was liked: 488
There is nothing wrong with playing against ducks. --Mickey Mouse

Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #7 Posted: Thu Aug 12, 2021 6:16 am 
Lives with ko

Posts: 198
Liked others: 4
Was liked: 16
In even games, new stuff is always important but in handicap games the most important is to learn how to use the stones together. So old or new is not the point at handicap such as 4 stones.

Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #8 Posted: Thu Aug 12, 2021 11:16 am 
Lives in sente
User avatar

Posts: 714
Liked others: 109
Was liked: 138
Rank: Shokyu
Universal go server handle: CDavis7M
John Fairbairn wrote:
It's many years since I translated the book, but my memory of it is that it doesn't even mention joseki or fuseki.

Thank you for the translation. It was a great find for me.


From what I have read so far, I've seen no use of the words "joseki" or "fuseki" or any translation that I would recognize. But both joseki and fuseki are discussed often . For joseki, the response to a kakari with a center pincer (10-3 point) is discussed often. Shuho says that it "has been a popular way of playing in recent times and is not bad" ("not bad" as opposed to "good" is clear enough for me). The ogeima response to a kakari is also discussed, as is the tsuke-nobi joseki. Fuseki is discussed in which joseki is played or not play. For instance, not playing the ogeima response when that side is already occupied by the opponent's stone, attaching to the stronger stone in the tsuke-nobi, which joseki is good to play if you have a stone on the other side (the attachment is "good"), and when it is good to sacrifice a stone for a big opening point, and so on. These points all seem valid today.

This is of interest to me because I have been playing Handicap Go recently with a strong player well versed in AI and I was surprised by how similar today's Handicap Go was to Hoen Shinpo. Especially in contrast to Shuho's even games against Shuwa and Shusaku.

My original question should have been: Has AI changed Handicap Go much or does the difference in skill between the players still lend itself to the same opening strategies (joseki and fuseki) that Shuho taught?

I suspected that Hoen Shinpo's teachings are still valid for Handicap Go. And it seems some of you agree. My thanks to everyone for your comments.

By the way, if anyone can point me to commentaries on Shuwa's games besides Hoen Shinpo, Invincible, and Appreciating Famous Games, I'd appreciate it. I can't find anything in English nor can I find anything on Amazon Japan.

Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #9 Posted: Fri Aug 13, 2021 8:12 am 
Lives with ko

Posts: 198
Liked others: 4
Was liked: 16
Wouahh this book looks awesome. Unfortunately cannot register on the site...

Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #10 Posted: Fri Aug 13, 2021 9:55 am 
Lives in sente
User avatar

Posts: 714
Liked others: 109
Was liked: 138
Rank: Shokyu
Universal go server handle: CDavis7M
lichigo wrote:
Wouahh this book looks awesome. Unfortunately cannot register on the site...

Upon Marcel's suggestion I found 古碁×AI 秀和と秀策に学ぶ勝負術 on Amazon JP: https://www.amazon.co.jp/dp/4839977321/. You'll need to make a new Amazon account but shipping is reasonable (~$15), they deliver in 2-7 days usually, a bit slower for flat media, and the Japanese know how to package books. I have a few books and magazines waiting in my cart because shipping doesn't seem to go up much or at all when you add more items.

There are a few example pages to read on Amazon, including mention of the ear-reddening move, which I was also discussed here on L19 using AI. I do not read Japanese. I only know enough to read tsumego problems and whether there is a ko. This book seems to have a lot of expanded discussion without saying much. The amount of text is too much for me while translating. I'd prefer Shuho's brevity. And I am not as interested in the AI analysis. I appreciate Marcel's suggestion though. If anyone orders the book, please share a review of it.

Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #11 Posted: Fri Aug 13, 2021 1:39 pm 
Oza

Posts: 3644
Liked others: 20
Was liked: 4620
Quote:
By the way, if anyone can point me to commentaries on Shuwa's games besides Hoen Shinpo, Invincible, and Appreciating Famous Games, I'd appreciate it. I can't find anything in English nor can I find anything on Amazon Japan.


There is quite a lot of detail of Shuwa's life in my Meijin of Meijins. Game commentaries were common in old magazines, especially by Kato Shin, but books are surprisingly rare. There is, of course, a volume in the magisterial Nihon Igo Taikei series (commentaries by Sugiuchi Masao), there are a few in the Castle Games (by Segoe et al.) and there is a small paperback by Fukui Masaaki, which has only a light dusting of comments as Fukui is more interested in historical details.

One problem for Shuwa was that he played too many games! Prof. Araki Naomi was the great collector of Edo games and he remarked that he thought nobody in olden times played as many games as Shuwa - he had some 650 as of them. More have since been found. But Araki died before he finished work on the Shuwa collection (in 1962). His widow passed on to the publishers what he had done - about 450 games from memory - and that remains the standard work. It is hard(ish) to get in Japan but Chinese sites are selling photocopies today. It was too daunting to work on and republish a tome of 650 games in the decades after Araki, but is even more unlikely in the modern age, and publishing a sgf collection would be the height of financial stupidity.

I think this situation has impinged badly on Shuwa's reputation. It seems that many of his best games (i.e. in his later career) are among those unpublished. However, he is certainly esteemed. Fukui's assessment seems reasonably typical: Shuwa's style was airy (funwari) in a good way, as elegant as a well-made soufflé. Rather AI-ish, too.

This style seems apparent in the following game, which was a Castle Game against Sakaguchi Sentoku, who proved a stern opponent for Shuwa and so brought out the best in him. They were both 7-dan at the time but the game is marked as Sentoku taking a 先先先 handicap (i.e. senaisen; ferreting out the explanation for this is the sort of detail Fukui likes to explore).

There is no Direct 3-3 here, but an equivalent early position arises by transposition after move 5. Further AI-looking moves by Shuwa include the two shoulder hits. There is a sort of honeycomb feeling about the shapes of his stones - no stodginess, pure lightness (it may be significant that Shuwa's opus magnum was called Go Purity (Kijun). FWIW I find Nakamura Sumire's style very similar. She is certainly an absolute shape wizard, of Harry Potter proportions.



According to Fukui, move 17 was well timed, 48 was maybe a bit too airy (at 49 was better), 60 and 62 were clever moves but 63 was also a good shape-busting move, 96 was to forestall warikomi at L16 and 98 punctures the moyo soufflé Black thought he had made with 73. White 100 signalled victory. Fukui says Shuwa probably knew he had won at that point.

Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #12 Posted: Sat Aug 14, 2021 7:15 am 
Dies with sente

Posts: 83
Liked others: 6
Was liked: 65
Rank: now 1kyu-ish
John - Are you sure about 450 games? - on GoGoD Winter 2019 I can only find 220 games under Shuwa. I am not aware of him changing his name, as in the case of Honinbo Shusai where you also need to search on Tamura. The GoGoD games for Shuwa start in 1832 and end in 1873, which fits with Sensei's where his life span is given as 1820-1873.

There is an English commentary on his 1840 game with Gennan in the series "Famous Games Ancient and Modern" in the magazine "Go Review" - issue 1969-05. This game lasted 71 hours.

There is one other book (in Japanese) on his games:

Fukui Masaaki 2009 287 pages hardback - 10 games with detailed comments - 175 pages and 35 games with a few comments in 100 pages.

Fukui Masaaki also wrote the volume on Shuwa in the Nihon Kiin Series, which is the one I think John mentioned. This has 55 games in some 210 pages.

https://tchan001.wordpress.com/2011/07/ ... s-8-books/

There is a copy of his games from Prof. Araki Naomi's collection in Japanese for sale at:

https://buyee.jp/item/yahoo/auction/p83 ... ch_suggest

this is in 4 volumes - note the numerals on the diagrams are Japanese.....

The Covid lockdown has ended here in England, but it has got me into the habit of digging into various things, such as the classic period of Japanese Go....

Best Wishes - John


This post by John Tilley was liked by: Ferran
Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #13 Posted: Sat Aug 14, 2021 10:05 am 
Oza

Posts: 3644
Liked others: 20
Was liked: 4620
Quote:
Are you sure about 450 games? -


I wasn't sure, but a quick check the figure puts the true figure at 491 published under Araki's name.

The GoGoD figure is not the one to use. Mark's death robbed us of completing the Shuwa task, and as it happens also put a big dent in the Sakata and Fujisawa totals. I continue to transcribe but my own interests relate to old Chinese and the middle third of the 20th century in Japan (I'm especially keen on Segoe).

However, someone is currently transcribing the Shuwa collection for me, though I expect that to take about two years. The current GoGoD total is 236, reflecting some recent discoveries.

A new GoGoD issue is currently being prepared.


This post by John Fairbairn was liked by: Ferran
Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #14 Posted: Sun Aug 15, 2021 1:27 pm 
Lives in sente
User avatar

Posts: 714
Liked others: 109
Was liked: 138
Rank: Shokyu
Universal go server handle: CDavis7M
John Fairbairn wrote:
There is quite a lot of detail of Shuwa's life in my Meijin of Meijins. Game commentaries were common in old magazines, especially by Kato Shin, but books are surprisingly rare. There is, of course, a volume in the magisterial Nihon Igo Taikei series (commentaries by Sugiuchi Masao), there are a few in the Castle Games (by Segoe et al.) and there is a small paperback by Fukui Masaaki, which has only a light dusting of comments as Fukui is more interested in historical details.


Thank you for your help John and for the summary of Fukui's commentary. I appreciate that! I went ahead and bought a paperback copy of Meijin of Meijins from Amazon. I'm wondering how it compares to the Kindle book titled "Life of Honinbo Shuei" and whether there is any overlap with the large Games of Shuei paperback. As for the other books, of course I had no luck in tracking any of them down. Though I did discover that some library in Cleveland has several old Japanese Go books.

It's unfortunate that many of his Shuwa's games are unpublished but what has been published will be enough for me. His style just resonates with me. I cheer for Shuwa against Gennan Inseki but also against Shusaku. It's interesting that Nakamura Sumire reminds of you Shuwa. I have reviewed/watched a few of her games in Go World and on the Nihon Kiin Go Channel on YouTube but now I will pay more attention.

Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #15 Posted: Sun Aug 15, 2021 2:04 pm 
Lives in sente
User avatar

Posts: 714
Liked others: 109
Was liked: 138
Rank: Shokyu
Universal go server handle: CDavis7M
John Tilley wrote:
There is one other book (in Japanese) on his games:
Fukui Masaaki 2009 287 pages hardback - 10 games with detailed comments - 175 pages and 35 games with a few comments in 100 pages.

Fukui Masaaki also wrote the volume on Shuwa in the Nihon Kiin Series, which is the one I think John mentioned. This has 55 games in some 210 pages.
https://tchan001.wordpress.com/2011/07/ ... s-8-books/

And thank you John. I can actually find copies of these books. I believe that the first book you mentioned is 名人・名局選 秀和 単行本 by Fukui Masaaki (福井 正明). This book is part of a series and from reading reviews of other books it seems to be a rework of the Nihon Kiin series that you mentioned, so a rework of 堅塁秀和.

Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #16 Posted: Sun Aug 15, 2021 3:54 pm 
Dies with sente

Posts: 83
Liked others: 6
Was liked: 65
Rank: now 1kyu-ish
You are correct about the title of the first Fukui book - the hardback one. The main difference between the two books by Fukui is that the first one I mentioned has lengthy analysis and comments on the games - the first game has 15 pages and is 13 figures and 23 diagrams long.

The second book has about 5 figures and 5 pages per game and no explanatory diagrams.

Fukui wrote a series of seven volumes on Classical Japanese Go - Jowa, Dosaku, Great Senchi, Shuwa, Shusaku, Shuho and Shuei whereas the Nihon Kiin series has eight volumes - you gain Genan Inseki and Chitoku, but lose Senchi.

I haven't attempted to list and compare the chosen games between the volumes (yet).... Its always interesting as to the games chosen for these anthologies.

Take care - John

Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #17 Posted: Mon Aug 16, 2021 11:49 am 
Oza

Posts: 3644
Liked others: 20
Was liked: 4620
Quote:
There are a few example pages to read on Amazon, including mention of the ear-reddening move, which I was also discussed here on L19 using AI. I do not read Japanese. I only know enough to read tsumego problems and whether there is a ko. This book seems to have a lot of expanded discussion without saying much. The amount of text is too much for me while translating. I'd prefer Shuho's brevity. And I am not as interested in the AI analysis. I appreciate Marcel's suggestion though. If anyone orders the book, please share a review of it.



I haven't got round to reading it properly yet, and I'm not sure when I will - all the numbers and graphs represent trials and tribulations for me and I haven't got a magic flute to help me with the task of overcoming them.

On the plus side, part author Ohashi Hirofumi is an engaging Papageno-like figure, and certainly knows the AI field. He is the go-to man from Japan whenever AI seminars and tournaments send out invitations (via Hedwig, no doubt :)). He wrote a "Go AI Encyclopaedia - from AlphaGo to Zen" (the wrong chronology but A to Z had too much pull for him or his editor). Frankly this was a bit of a jumping-on-the-bandwagon pot-boiler, certainly by his standards. A very much more interesting book on "New Fusekis in the AI age" followed. Rather than trying to tell us what the new principles of fuseki should be, he looked instead at unusual fusekis such as o-takamoku (6-4), the tiger-jimari, 5-5, tengen and the Black Hole, and tells us what AI says about these openings. Not being a proper student of the game any more I never read all of it, but I read enough to be convinced it was at the least a very entertaining book. As I say, his whole tone is "Der Fusekifänger bin ich ja, stets lustig, heissa hopsa-sa!" Whether it is also useful I don't feel qualified to judge.

The latest book, invoking Shuwa and Shusaku, is one that I think I will get round to reading (the history pull is too strong) and I'm already certain it will be very useful. But this is not quite Ohashi's usual hopsa-sa style, no doubt because the book is almost entirely a conversation between him and co-author Terayama Rei, who is still only 20 (but already 6-dan). This means there is no solid presentation of theory or other ideas. You have to glean these from throw-away comments in the conversation. But there's gold in them thar comments (e.g. Ohashi's observation that AI prefers high extensions to low ones).

Actually, despite the title and the presence of graphs, in many respects the book is not even about AI. The book has a sub-title that says you can become strong just by playing over old games. That is really the main message (and the stress on improving by playing over pro games is one that I've seen repeated over and over in recent months). AI is just a tool to help you do that, by enabling you to look deeper and more accurately. Having said that, there is a human endgame brilliancy here that Katago 6809 (the version used) allegedly missed, despite searching for over a million moves.

I don't think it's a spoiler to say the humans come out rather well in this book. It wouldn't have been worth writing otherwise. But even that's not the real point, which is still that the way to improve is to play over these games with the latest tools at your disposal. You still have to think for yourself.

The structure of the book:

Introductory Section: The Ear-reddening game
Section 1: Shuwa
Section 2: Shusaku
Section 3: Shuwa vs Shusaku.

Dotted throughout the book (i.e. between the games, which do not have conventional commentaries) are also what would normally be mini-essays, but these too are in conversational format. They cover on the one hand things like how to use AI to study old games, AI and thickness; but on the other they talk about Edo go history.

Because of the conversational nature of the book, I think you will need to be able to read Japanese beyond the usual go-words level. And there are no variation diagrams to provide an alternative to what the text says. You may get something out of the graphs, but actually there aren't as many as I may have implied (one is too many for me), and you could run your own AI to generate pretty similar graphs yourself, I imagine.

But if you can read the text, even with my cursory engagement with it I'd recommend the book very highly, both as entertainment and as a way to improve.

Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #18 Posted: Mon Aug 16, 2021 10:21 pm 
Lives in sente
User avatar

Posts: 714
Liked others: 109
Was liked: 138
Rank: Shokyu
Universal go server handle: CDavis7M
John Fairbairn wrote:
There is quite a lot of detail of Shuwa's life in my Meijin of Meijins.


Well, that was depressing.

My hype went up in flames, so to speak.

Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #19 Posted: Tue Aug 17, 2021 3:47 am 
Oza

Posts: 3644
Liked others: 20
Was liked: 4620
Quote:
My hype went up in flames, so to speak.


Worse for him, though - his godown went down in flames.

I have a question for the AI buffs. Having posted the (semi-)review above, I bestirred myself enough to read some more of the book in bed. It was numerology stuff, and so more trials and tribulations, but a pre-bed toot on a magic harmonica instead of a flute gave me some inspiration.

Ohashi (I assume it is he - he just says "I") points out that the choice of whether to look at win rate or points difference (in Katago) depends on the state of the game. Points difference should normally be used as this is more familiar to a human, but AI is unreliable as regards points difference in intense fighting situations, such as capturing races and ko fights (and even may make inaccurate moves). Then you should rely on the win rate. I can follow that.

There is, however, I would suggest, a powerful psychological reason for preferring points difference, which he does not discuss directly. Herein lies my question. He shows graphs with both win rate and points difference, the lines superimposed. The win rate line often veers up and down wildly with huge fluctuations, making it look as if one side is far ahead it's not worth playing on, or that a player has made a truly horrendous mistake. Yet the points difference line typically trundles on, on an almost flat path, telling us that the game is really rather close, and any points change is in a range a typical amateur wouldn't even notice..

Ohashi says that, by the endgame, in modern komi go, if a player is leading by half a point, that may represent about 90% win rate. OK, but then he says, "If he loses 1 point, this will drop 80% and may become 10%." Forget the mix-up between % and percentage points - Japanese are as prone to grocer's mathematics as we are. But in my grocer's head, I say "losing a point in a half-point game means the lead switches" so I expect the win rate now to be 90% for the other guy. I assume Ohashi may have been a bit sloppy and omitted some detail about the 1-point mistake (sente/gote?), but I also assume that I have probably missed something. What?

There are a couple more statements by him that have not yet passed the Pearly Gates test for entry into my brain. One is: "In the case of no-komi go [where jigo is possible], if you make a 1-point loss from a win rate of 90%, you go down to 50%, or 0 points. To a mind used to counting as in modern go, when you look at the count in a no-komi game, don't forget that if it is a close game the amplitude of the swing is about half."

I can sense some sense in that, but basically it's smoke and mirrors to me. Can someone provide the baby steps to understanding?

A further remark: In the case of 1-point [no-komi] game, we can perhaps say that with a win rate between 25% and 75% there is a high probability that it will be a jigo." Again, I can feel an inkling of understanding, but a voice in my head says, "So what can we say about the 50 percentage points in that range - are they just statistical noise?"

Here are a couple of graphs. The thick line denotes win rate and the thin line is points difference. The middle dotted line is the 50% bar.

In the first case, we can see the possible psychological impact if we rely on win rate rather than points difference.

Attachment:
Ohashi1.jpg
Ohashi1.jpg [ 70.21 KiB | Viewed 15214 times ]


In the case below, we can see that Black (Shuwa) apparently made not a single significant mistake. There are similar examples in other games, which is why I say the humans seem to come out of this book rather well.

Attachment:
Ohashi2.jpg
Ohashi2.jpg [ 50.54 KiB | Viewed 15214 times ]


But these graphs also reveal what I think is a defect of the book. There are no scale markings, and so it seems that in one of the above (non-handicap) games, Black started off with a bigger win rate than in the other. There are also no move numbers, and while it seems likely that the whole game is represented, we cannot be certain in some portions of the book. FWIW, in the case of the "complete victory" by Shuwa (then "at his peak" say the authors), the margin of victory was apparently 5 points, but the graph line shows a gradual increase, which implies the initial advantage to Black was less than 5 points????

Note: I can't find a way to turn the pictures round. They appear in the right orientation elsewhere on my system.

Top
 Profile  
 
Offline
 Post subject: Re: Hoen Shinpo--Are historical handicap openings still good
Post #20 Posted: Tue Aug 17, 2021 5:12 am 
Lives in sente

Posts: 896
Liked others: 22
Was liked: 168
Rank: panda 5 dan
IGS: kvasir
John Fairbairn wrote:
Ohashi says that, by the endgame, in modern komi go, if a player is leading by half a point, that may represent about 90% win rate. OK, but then he says, "If he loses 1 point, this will drop 80% and may become 10%." Forget the mix-up between % and percentage points - Japanese are as prone to grocer's mathematics as we are. But in my grocer's head, I say "losing a point in a half-point game means the lead switches" so I expect the win rate now to be 90% for the other guy. I assume Ohashi may have been a bit sloppy and omitted some detail about the 1-point mistake (sente/gote?), but I also assume that I have probably missed something. What?


I think what you are missing, actually you don't seem to be missing anything because it is a case that you are adding sente / gote considerations were there is none. The predicted points and point differences are estimates of the final result of the game. If you had a choice of gote moves x and y, where x > y, but choice y your point loss is approximately y - x. If you instead make a mistake of sente or gote, then the estimate is still of the final result of the game, but one one component of the point difference will be an estimate of the value of sente. Basically, you can speak of 1 point mistake without specifying sente or gote, it could have been that you played a move in sente that is just 1 point less than it could have been or you could have played a really big move in gote and this 1 point is the difference compared to playing some sente moves first.


The "point difference" and "percentages" are both estimates that are
1. affected by uncertainty
2. are mapping win-loss (or 0-1 result of the game) in two different ways that introduces ambiguity of presentation

The uncertainty is less toward the end of the game and in quiet positions, it also depends on the quality of the analysis. The percentages should get closer and closer to 0% or 100% as the game moves closer to the end, even if the game is quite close.

The ambiguity of mapping a win-loss result to a point difference can lead to values that are difficult to interpret. For example the swing between who wins a capturing race can be heavily biased in terms of points, as was mentioned by Ohashi, basically what does it really mean to say that the average of x and y is (x + y) / 2, and that this is the outcome of the game, if that is not a likely outcome of the game and only x or y are plausible outcomes. This is just a simple example to show that the point estimate can be almost meaningless.

We probably shouldn't discuss "percentages" or "point differences" very much when reviewing games. I sometimes feel one can just as well say "I checked it with a computer" or "computer approved" than say "a is 16.4% better than b" or "a is 3.4 pts better than b".

Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 20 posts ] 

All times are UTC - 8 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group