Originally featured on my study journal, I'm turning this into a series of exercises. This year I'm playing 1 game a day (10 games behind) and reviewing them with Katago, in particular the biggest mistakes, either swinging the probability of winning or losing a major number of points. It's those that I'm turning into ABC-exercises. One is my move, thus the mistake. Another is KataGo's move. And then there's another one, just to make it more interesting.

Click Here To Show Diagram Code

[go]$$ Mistake 1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . b . . . . . |
$$ | . . . . O . O a O . X X . X O O O O . |
$$ | . . O O X O O X O . O X X O O X O . O |
$$ | . . O X X X X X . O O O X X O X O O X |
$$ | . . . . . . . O . O O X X . X X X X X |
$$ | . . O O X . . . O X O O O X . . . . . |
$$ | . . . . X . . X X X X X X . . . . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . O . X . X X X . |
$$ | . . . O X . . . . X X O . . . X O O . |
$$ | . . O X X . . . X O O . c X X O O . . |
$$ | . . O O X . . . X X O O . O O . . . . |
$$ | . O . . . . . . X O O . . . . . . . . |
$$ | . O X X . . . . . X X O . . . . O . . |
$$ | . O O X . . . . . X O . . . . X O . . |
$$ | X O X O . . . . . X . O . O O O . O . |
$$ | . X X X X . . . . X O O X . X X O . O |
$$ | . . . . . . X X X O . O X . X . X O . |
$$ | . . . . . . X O O O O . . . . X X O . |
$$ ---------------------------------------[/go]

Should White connect at ''a'', atari at ''b'' or play ''c''?

In light of this post https://lifein19x19.com/viewtopic.php?p=264182#p264182 the correct move must be "a". Move "c" is just 2 points reverse sente I think (edit: actually M9 is not a point, unless White plays at N10 later, but anyway it is not very big), so much smaller than saving the two stones H15.

I think c is good. Threatening either to cut off two stones or to break into the white territory with two peeps from inside.

It's White to play...

Let me toss an idea out for discussion: the biggest mistake here is to make an ABC of mistakes.

I obviously don't know what will be featured in later examples, but I have very long experience of mistakes. I even made one in 1999.

My experience of mistakes, once you strip out those made because of carelessness, tiredness and such like, is that the most important are those where you an say: "Oh, I didn't realise you could do that!" In the same way, the moves in commentaries, joseki books. L&D and everything else that have made me stop in surprise (and still remember to this day) are moves where my reaction is: "Oh, I didn't realise you could do that!"

When I look at the response of pros to the unexpected plays by AI bots, over and over again what I see is that their response boils down to: "Oh, I didn't realise you could do that!"

I am inferring that Dieter's responses in his examples were of the same type.

What this seems to mean, to me, is that our most fundamental mistake is not including the surprising moves in our list of candidate moves. I suspect there is a subtle difference between the pro and amateur cases: pros have blind spots because they have not built these moves into their intuitions yet; amateurs seem caught out most by not realising how big certain moves can be. But, either way, the problem is a shortage of candidate moves in our heads.

If that thinking is along the right lines, it seems that restricting the candidates to ABC is the very opposite of the right way to go. The first step should surely be to extend our list of candidates moves to ABCDEFGH and beyond. The next, and more important, step of course is to rank those moves, but you can't rank them unless they are there in the first place.

I wonder, therefore, whether a more fruitful approach might be to list "all the moves I considered were" against "all the moves katago considered" and see if some pattern emerges, "all" being simplified to e.g. top ten rather than top three.

And if you didn't consider as many as a top ten, is that not part of the problem?.

John, this series intends to consistently look at the data of a 2d player (me) and understand what kinds of mistakes they are (I am) making. Rarely they fall into the category "Oh I didn't realize you could do that". They are rather "I know this but failed to apply my knowledge" or "I should have read this because the situation looks suspicious indeed".

The "Oh I didn't realize you could do this" is ubiquitous but the swing values are rather small.

If you think I am making a mistake by looking at my mistakes, fine. I don't. I can do it in private if you think I'm littering the forum. However, when looking into it privately, I thought "this is the kind of material you rarely see in instructional articles". So I gave it a shot. If there's low interest, I'll stop posting.

Please keep posting, I am interested. All my games are like that: I have several options A, B, C and I never know which one is best.

That's an oddly prickly reaction. Most of my own posts can be construed as a desperate attempt to stimulate discussion here, so I am hardly likely to be suggesting you are littering the forum. Since my attempts to get discussions going are almost always rebuffed, maybe I should be the one to stop posting.



This I actually found very interesting (if it's genuinely reliable), and illustrates perfectly the value of discussing, adding to my own (and others'?) knowledge. It engenders the further point for discussion: if that type of mistake is so ubiquitous, why is it not being looked at more often?

And yet another point that flows from discussing: if you find the ABC approach valuable (and I never said that was a mistake - I just suggested widening the scope) but rare, I can suggest you look at some of the Ishi Press books. I think Breakthrough to Shodan was of that type, and (I memory serves) there were several series of tat type in Go World.

Please don't. In this case you started out by calling the theme/approach of the series a mistake. So yeah, that prickled me a little bit. But it fades out fast.



I'm not sure if I expressed myself well.

In this ABC series, I'm zooming in on moves I played, which were evaluated way worse than its preferred move, i.e. big mistakes. I just checked the 12 examples I had prepared

In 7/12 cases I had the preferred move on my radar but thought something else was more urgent or affordable
In 3 cases I had no radar, I wasn't playing on autopilot.
Only in 2 cases KataGo's move was of the category "Oh I didn't realize you could do that"

This small sample suggests that my candidate selection is not as bad as I thought, or that it's not coming to the surface as much when sampling big mistakes.

Your question begs an exercise on my end: during reviews keep a tally of 1) I played the best move 2) I considered the best move but didn't play it 3) I didn't consider the best move + 2a/b-3a/b my move was significantly/not significantly worse

I will echo this idea, although I think amateurs may also be caught by evaluating areas as being larger than they really are because they don't know of the existence of a critical weakness. I'll give an example where "I didn't realize that". I saw it about 20 years ago and I still remember it vividly.

The basic position is here, and the question is what kind of scope for action there is on the right side.

Click Here To Show Diagram Code

[go]$$
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . O . O . . . |
$$ | . . . . . . . . . . . . O . O . O . . |
$$ | . . . . . . . . . . . X . O X O O . . |
$$ | . . . . . . . . . . . . X O X X X . . |
$$ | . . . . . . . . . . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Clearly there's scope for play and I naturally focused on the points marked 'a' as well as few others. But in two pro games the initial move was a deep invasion, but elsewhere. I'll hide the continuation to let people think.

I think what we don't see is this ko:


Now that I'm out of the initial publishing frenzy, I can take a step back to appreciate John's point.

For educational purposes I limited the choices to 3 because I wanted to highlight my big mistake vs the proper move and then all good things come in 3.

That last bit is where the space opened up. When it's about playing good go, for educational purposes it might be better to offer all the possibilities. But that's another exercise than what I wanted to show.

I thought that if I would show the mistake and the good move only, the exercise would become too easy.

To comment on this:



While it's important to eliminate big mistakes, I think that to improve it is necessary to look at small mistakes as well. Typically when a player is several stones stronger than another, Katago's graph has more or less a constant slope, plus or minus a few accidents, showing that the stronger player consistently makes better moves. Imagine if all your moves were 1 point better on average, what would be the difference after 100 moves?

To confirm that impression I analyzed a game I played last Sunday. First, the game without comments (186 moves). This game was EGF-rated, with 1h main time + Canadian byo-yomi 15 stones/5 minutes:



And then the game with comments (only up to move 126) with a tentative explanation for each mistake by White.



Almost all the game was quite balanced: until move 176, none of the players made 10+ point mistakes but both made a roughly equal number of 1-5 point mistakes, which could be categorized as followitis, failure to consider tenuki, failure to look at the opponent's weaknesses, etc.

So I would say that correcting our way of thinking about the game could potentially eliminate a large number of small/medium mistakes, which overall would have more impact than eliminating a small number of big mistakes.

Now, I estimate that we are about 4 (or maybe 5?) stones weaker than Knotwilg, so our fundamentals are not as good, but still I suspect that the above conclusion still holds at low dan level.

Hi JLT

The major reason for me to zoom in on "big mistakes" is that KataGo (or any AI) has a certain margin of error, which is higher in case of few playouts. When doing a full game review, I'm not regularly pausing to get huge playouts, although I will pause around the spikes to verify where the problem really started.

My threshold is around 5 points AND 10%. Why AND? Because a >5 mistake with a low change in % means the game is unbalanced already. And a >10% for a 1 point mistake means the game is still playable.

Next I'm looking into all games, finding the three biggest mistakes. I'm at 80 games now so I already have 240 mistakes to learn from. Patterns emerge and if I can correct these, I'll become better. That's the big IF.

Learning from KataGo's half point improvements would require lifting my level of understanding to pro level. At my level, it is better to regard them as noise.

Thanks for giving so much attention to the thread! It encourages me to continue.

Hmmm. I think that the colors of the moves are reversed in that diagram. Here is the diagram with the first move colored White.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

Certainly what works for different people is different. But for most people, my feeling is that this is a common misconception. I mean, consider this:

Click Here To Show Diagram Code

[go]$$c Is this a mistake?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . O . . . . . , . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . O X a . . |
$$ | . . . . . . . . . . . . . . . 1 . . . |
$$ ---------------------------------------[/go]

This move is judged to lose only about a point compared to connecting at "a" (which is more-or-less the best move on this board, in fact). But only a point! So are we wrong to spend the time to teach beginners to connect solidly on the second line as the default move except when there is a specific need for another move? I don't think so. This is a basic educational shape that is common - it occurs multiple times per game, and is easy to learn, and in combination with some other common edge patterns, helps build some foundational intuition for beginners about basic tactics near the edge.

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

1. Commonness of the shape - if a move in a particular shape is only a 1 point mistake but the shape occurs once every other game, then it could easily be many times more important than a tactical blunder that loses 20 points but where that particular tactic won't show up in that particular way in the next 100 games.

2. Ease of recognition and learning - if a move or concept is recognizable once you see it and fits well with your existing intuitions and knowledge so that you can learn it easily, it could easily be far more gain per time or effort expended than other scorewise-larger mistakes.

The ability to help with these two things is of course one of the reasons why having a stronger human player or teacher review your game can be far more effective than self-review with AI. But I can think of still a number of ways to partially get at these things with AI, if not so hasty to immediately filter by mistake size in points. I haven't played as much recently, but some things I've felt were useful personally in the past include:

* Scroll through the game-being-reviewed quickly and just see what the AI wanted to play and what its instincts were, and look for any moves the AI suggests that differ from yours, even if only better by a point, but where upon seeing the move and pondering it a little, it's like "oh duh, that shape is a lot better, I like that move a lot" or otherwise where it's clear upon seeing the move why it's better. You DON'T need high playouts for this, you're looking for major differences of instinct that you can absorb. Of course you might be wrong and not *really* understand, but if your brain is saying "I can intuit this move, I can learn it", that move probably *is* on average easier to intuit and learn.

* 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.

* 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. Those might be good points for learning. Of course, if the AI recommended variation is arcane and incomprehensible (and it's still arcane and incomprehensible even when you interactively take the opponent's side and play "what if" a little bit, which often clears it up), move on. But if it's clear, then that's a good place to start. For me, a lot of mistakes are fall into the category of "things you don't know you didn't know", but if you *do* know you don't know, why not take advantage of that? And if in fact you got it right, the fact you were uncertain maybe makes it still a good learning sample, even though it wasn't a mistake.

* Focusing mildly more on mistakes, even if smaller, in semi-common corner patterns or invasions or josekis or whatever. Patterns that are more common are more likely to be relevant in future games. Similarly for things in midgame fights where despite the fight itself being unique the shape or tesuji within that fight that was missed is recognizable and familiar in retrospect - being more common makes it more useful.

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.

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?

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.

Fair points.



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?




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.

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.