Dieter's ABC of mistakes - 1

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Re: Dieter's ABC of mistakes - 1

Post by Uberdude »

Well said lightvector. There are some 0.1 point mistakes that even 10 kyus can correctly identify. Finding small pointwise mistakes that standard human go theory has correctly identified and explained so that even weak players can get right is an interesting exercise. Sometimes it's interesting that the "wrong" answer is so little wrong that it reveals a misjudgment in the prior theory. Or it can just show the high fidelity of our theory.

Here's an example.
Click Here To Show Diagram Code
[go]$$c
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 2 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . b . 5 . . . . . X . . . |
$$ | . . 4 . . 1 . a c . . . . . . . . . . |
$$ | . . . 3 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Focusing on 5 (the slide of 3 being about a 0.4 point loss is an example of the old theory being wrong). This extension after making the slide is a fairly common mistake which I have highlighted and explained in teaching over the years. The explanation goes like:

If you play the slide of 3, then you should continue with a closer, more connected move like the (beginner 101) joseki at c, or maybe mention b too depending on audience. This is because the big extension leaves a weakness at a. If White invades here later and you've played the slide, then you are pretty much obligated to save the f3 stone because you can't sacrifice it on a small scale by jumping into the corner. This reduces Black's good choices in how to deal with the invasion and means he can't focus so much on building the lower right area. For example this sequence is one way to deal with the invasion (when White has the ladders) and black wants to emphasise building the lower right area and central thickness, trouble is losing f3 and d2 means White is happy to get a big safe corner (actually white may still spend a move here, but this is about securing the 5 stones, the corner is already secure with c3):
Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . X . . |
$$ | . . . . . . . 8 4 0 . . . . . . . . . |
$$ | . . . O . . 7 2 3 X . . . . . X . . . |
$$ | . . O . . X 9 1 5 6 . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Compare and contrast to the same thing happening without the slide for 3-3 exchange. Now the corner is not yet White safe territory, black could play 3-3 (a) himself to live there, so White will usually spend a move at b to secure it, and even now there's still aji at the 3-3 point to use later (e.g. a move at c could threaten some funny business in the corner). Black playing d2 to give white a stone at c3 would be terrible now, but that's what's happened above.
Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . c . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . X . . |
$$ | . . . . . . . 8 4 0 . . . . . . . . . |
$$ | . . . O . b 7 2 3 X . . . . . X . . . |
$$ | . . a . . X 9 1 5 6 . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
So by playing the slide black has made the f3 stone harder to sacrifice in a good way. Stones which are a liability: you need to save them but there's not a good way and you'd rather not, are called heavy stones. So we could say by sliding black has made f3 heavier. The reason the joseki is to extend closer with the 2 space jump is it is better connected than the larger 3 space: once you've played the slide you need to be consistent. If your want to play the big extension that's a fine move, but do so directly without making the slide exchange first. Making your stones work together in a consistent plan, and heavy stones, are 2 important topics you'll find keep cropping up. This non joseki is a good place to learn about them.

Here endeth the lesson.

That's my pre AI explanation (and I don't think AI refutes it) of what I think is correct, useful, and comprehensible theory for players even as weak as 10kyu. How much of a mistake does KataGo say 5 is? About 0.2 points. So am I going to stop teaching this because that's small and 10 kyus make 40 point mistakes in fighting and pros make 5 point ones? No. Not only is the particular shape a common one that's good to learn, the general principles of consistency and exchanges making a stone harder to sacrifice are hugely valuable. Will a 10k doing AI self review figure this out? No, human teachers are still necessary. But by not skipping this mistake they keep making as only -0.2 maybe they ask a stronger friend or post on a forum asking about it and then can get some useful human teaching.

P.S. After the slide, the 2-space HIGH extension is one which is/was rarely seen in strong play. I also learnt this as a no-no, similar to the 3-space do it without the slide if you want to do it. But it doesn't have the invasion weakness of the 3-space, so the logical argument above doesn't apply. One argument which does apply is it leaves the l3 invasions, and if you kick that at k3 then j4 ends up in a locally bad kosumi shape next to the white nobi. I seem to recall reading, probably in one of JF's books, that Go Seigen was an advocate of this high 2 space with the slide. And guess what, AI likes this move the most of all the lower side extensions! (top left 3-3 number 1 though, quelle surpise, and d7 shoulder hit also likes). Yet another example of Go Seigen's genius AI premonition.
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Re: Dieter's ABC of mistakes - 1

Post by Knotwilg »

Edit: removed the part that was responding to lightvector because I think I missed something in his answer.

I'm quite surprised though that the "high extension after sliding" in Uberdude's example is only a 0.2 error. Surely when doing tewari, sliding after the side joseki will be much worse than invading the corner? Which means there are other things to take into account here than the sequence shown?
Last edited by Knotwilg on Thu Apr 15, 2021 1:16 am, edited 1 time in total.
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Re: Dieter's ABC of mistakes - 1

Post by Uberdude »

Knotwilg wrote: I'm quite surprised though that the "high extension after sliding" in Uberdude's example is only a 0.2 error. Surely when doing tewari, sliding after the side joseki will be much worse than invading the corner? Which means there are other things to take into account here than the sequence shown?
Interesting isn't it? :) My sequence shown is not of course the full or even major reason why slide and big extend is bad in AI's eyes, it's designed to illustrate, with a reasonable local continuation that could occur later, the "slide exchange makes f3 heavier" concept. I quickly checked the difference between those 2 diagrams with KG and it was about 4 points. Because the first variation diagram is so bad for black, KG suggests not even attaching on top of h3 invasion but the e4 shape building, allowing white to jump out and starting a fight. So the slide and extend is not so bad (just -0.2), but to use it well (and stop that -0.2 turning into a -2 and then a -4) black needs to abandon the standard way of using that extension and alter his play to be consistent with the slide and make all the stones work efficiently.

Also I think a considerable reason for AI not thinking it's so bad is to do with the slide 3-3 exchange being not all bad: yes it loses the chance to 3-3 invade, but it also stops white's kick which black is not 100% obligated to answer by extending up, but if we assume black would then it's a double sente exchange with pros and cons either side. AI's eagerness to attach after approaching a 4-4 and knight answer can also be seen as wanting to avoid this white kick, with a move that is actually sente unlike the slide.
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Re: Dieter's ABC of mistakes - 1

Post by Knotwilg »

lightvector wrote: In general, I think focusing only on the magnitude of a mistake in points misses these two critical elements:

1. Commonness of the shape
2. Ease of recognition and learning
Fair points.
lightvector wrote: * Also in that quick scan, looking for moves with recognizable shapes that are less "oh duh" and more like "wow I didn't know you could do that, but I see why it works" or even "I don't fully understand this move, but I understand enough to know that if I were the opponent facing this move, I'd find it extremely annoying and hard to find a good response to". Those could be good to try in future games. :) Again, you don't need high playouts for this either.
AI clearly has opened up many new paths, closed a few others, reopened variations previously thought of as bad and given nuance to things considered bad, as they are still playable. But this is where it gets tricky - how to distinguish the playable from the consistently worse by only 0.5?

lightvector wrote: * Before looking at "the answers", doing a quick self-review pass to note positions where you were genuinely uncertain about the right shape, or the right tactic, or the right direction.
These are the so called "known unknowns" - and I agree they are again useful triggers for improvement, as you will link up with AI on something you were already aware of.

Now I am in a stage where after 20 years of stagnation at 1-2 dan I want to make an attempt at stepping up. For that I need to understand the major flaws in my thinking, which is more like the "unknown unknowns". Some of the big swings in KataGo's review are just blunders - nothing to learn there than paying more attention, although ... it's clear I'm not reading enough.

I'm still in the process of compiling these "3 major errors per game" and categorizing them but I can already reveal the 3 categories that have emerged from the first 50:

1. cuts & connections that have low value
2. cuts & connections that are important but where I'm doing so with bad shape
3. releasing pressure (live and let live), where I should have continued applying pressure, possibly sacrificing the pressuring stones later

1 & 2 confirm a known gap in my ability, and one which I think is insufficiently taught. Tsumego focus on life & death, or at least I don't know of a good vault of cut & connect problems.

3 is very instructive and reveals a conceptual gap. I've linked this to John's ijime concept although that may not include the sacrifice part. I'll give some examples later.
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Re: Dieter's ABC of mistakes - 1

Post by John Fairbairn »

3. releasing pressure (live and let live), where I should have continued applying pressure, possibly sacrificing the pressuring stones later

3 is very instructive and reveals a conceptual gap. I've linked this to John's ijime concept although that may not include the sacrifice part. I'll give some examples later.
You may be interested to know that this concept is a major one among the old Chinese masters, yet it is one that is absent, as an identifiable idea in its own right, in Japanese go.

The significant thing about the old Chinese commentaries, of which there are very many, is that they were written by the masters themselves, not by journalists or amateurs. We therefore get to see their own thoughts in action.

All these masters shared a common vocabulary. Their thoughts, as exposed by their words, can vary according to their strength and predilections, of course, but on the whole they do talk about the same things.

If you look at the 20 most frequent words in these texts, you will see something revealing. In the table below the first bracketed figure is the % occurrence of that character in the ancient commentary corpus. The second such figure is the cumulative frequency (so that if you know these 20 characters you will recognise a third of all texts - the total number of characters in the corpus is around 1,000).

1. 位: (2.82) (2.82)
2. 不: (2.78) (5.60)
3. 当: (2.31) (7.91)
4. 至: (2.20) (10.12)
5. 白: (1.98) (12.10)
6. 得: (1.90) (14.01)
7. 黑: (1.84) (15.85)
8. 大: (1.63) (17.48)
9. 子: (1.49) (18.97)
10. 紧: (1.42) (20.39)
11. 着: (1.40) (21.80)
12. 是: (1.34) (23.14)
13. 于: (1.34) (24.48)
14. 好: (1.30) (25.78)
15. 之: (1.22) (26.99)
16. 法: (1.14) (28.13)
17. 细: (1.12) (29.25)
18. 有: (1.09) (30.34)
19. 先: (1.07) (31.41)
20. 宜: (1.00) (32.41)

The commonest character 位 denotes a point on the board and is so common because the Chinese structure for saying e.g. "he should play at 12" requires them to say "12位". Second commonest is no surprise: 不 = not. Third commonest likewise unsurprising: 当 = should (as in "12 is bad; he should play..."). Many of the other words are easy to predict: Black, White, to, good and so on.

But 10th in the list is 紧 (above "good", "it", "at" etc) and 17th is 细.

These two characters can be regarded as essentially shibboleths for ancient Chinese commentaries. For 细 I have seen translations such as "meticulous", "precise", "exquisite" - basically following normal dictionaries. In fact it means "good technique". It is the go-to word for good tactics.

In a similar way, 紧 can be regarded as the go-to word for good strategy. If you look it up in a dictionary you will get renderings such as "tight." But in go it refers to applying pressure, keeping the pressure on, ramping up the pressure, and so on (but not by "pressing" in the sense of kake - 压 in Chinese).

The importance of this word is underpinned by many more comments to do with keeping the initiative and with timing than you would see in Japanese commentary.

I wouldn't class it as ijime. Ijime can certainly happen as a result of the pressure, but it is not the motivation.

My own preferred imagery is to think of applying 紧 (jin) as behaving like a sheepdog. It's a happy coincidence that go is the surrounding game and the job of collies is to put the sheep in a pen. It is also a nice analogy in that the dogs don't bite or kill the sheep (i.e. no ijime). And one dog controls many sheep - rather like "one man at the pass".

I think that this is a fruitful way to think about go, all the more so as it takes us outside the stifling tramlines of Japanese go.
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Re: Dieter's ABC of mistakes - 1

Post by dfan »

Thanks for the very interesting statistics and commentary, John. If (and only if) you have the time and motivation, I would love to see a sample position or two in which 紧 is used. Or maybe it is so common that it applies to pretty much all good play?

It is interesting, after seeing this discussion, that In-seong Hwang is constantly talking about "applying pressure" in his lectures and game reviews. Often this has to do with making contact moves (taking away liberties and claiming more space) when one's instinct might be to play more peacefully.
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Re: Dieter's ABC of mistakes - 1

Post by schrody »

I'm currently in the process of studying the middle game and have found Shuko's Dictionary of basic tesuji very useful. It includes a chapter on connecting and one on separating but, more importantly, it teaches you how to utilize the full potential of 'shape' in different situations and for different purposes. I haven't been studying it in great detail but even so I now have a better sense of shape when it comes to attacking and defending. I think tesuji problems in general are good for practicing various middle game techniques and shape. I've also bought but have yet to read Richard Hunter's Cross cut workshop. It might be a bit basic, but it looks like a good overview of crosscut patterns. Other tangentially related topics would be haengma, invasions and reductions.

In addition to analysing my games with AI, I'm using AI sensei's spaced repetition function. I make around 10 problems from each of my games with a focus on basics shapes & principles and to a lesser extent whole-board intuition (e.g. direction of play, whole board strategic decisions). I've found this to be useful as well.
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Re: Dieter's ABC of mistakes - 1

Post by Harleqin »

Interesting, what John explains about 细 is how I currently understand the japanese term »tesuji« (手筋).

The »whole board pressure« is something that I see in my own mistakes and lacking strategical view. I now think that this can take many forms: the most obvious is something like »ijime«, where a group can be harrassed for profit. However, I think this can also take the shape of the inverse: something like »shinogi« where you deny your opponent profit that they need to keep up. Likewise, just taking the right big point after a temperature drop can be seen as keeping up pressure. In some ways, this dissolves into obvious »ya gotta do what ya gotta do«, but I think that the feeling of pressure is something very palpable. Play moves that stress your opponent. Or, as some old chess master said: don't solve problems, create them!

About what mistakes to learn from: I am using AI-Sensei's training feature a lot, and what I take into my problem set is situations where I am surprised of the »correct« answer, and where I can work out a plausible reasoning for what makes it correct.
A good system naturally covers all corner cases without further effort.
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Re: Dieter's ABC of mistakes - 1

Post by John Fairbairn »

Interesting, what John explains about 细 is how I currently understand the japanese term »tesuji« (手筋).
Not wrong, but simple suji (technique) is a better equivalent. The te portion adds a nuance of extra craftedness or precision, i.e. extra-good suji.
Play moves that stress your opponent. Or, as some old chess master said: don't solve problems, create them!
I like that. The word 'stress' is especially apposite.
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Re: Dieter's ABC of mistakes - 1

Post by Shaddy »

dfan wrote:Thanks for the very interesting statistics and commentary, John. If (and only if) you have the time and motivation, I would love to see a sample position or two in which 紧 is used. Or maybe it is so common that it applies to pretty much all good play?

It is interesting, after seeing this discussion, that In-seong Hwang is constantly talking about "applying pressure" in his lectures and game reviews. Often this has to do with making contact moves (taking away liberties and claiming more space) when one's instinct might be to play more peacefully.
The concept In-seong is talking about is probably the same one. When Chinese teachers want you to play one space closer to the opponent's stones or to attach instead, 紧 is the word they use. It has connotations of keeping sente, particularly.
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