This innocuous-looking position brought up several big surprises for me.

Black to play. Before you go on much further, try to predict Black's next play and, more importantly, say why (just theory - no fancy tactics required).



The first surprise for me was how dismissive author Yokota Shigeaki was of a pincer. Because I was in the midst of reading his book on thickness, I knew what the desired answer was, but I still had an inkling that a pincer was a valid idea - e.g. make territory while attacking. But Yokota said that the answer was as shown below, and that he believed 10 out of 10 pros would play that move.



The reasoning, which he explains convincingly in his book, is that you use 4-star or 3-star thickness (this is 4-star, the top mark) by pushing the opponent towards it. OK, but his 10 out of 10 claim got me to turn to the database and there were a couple of surprises there. First, this position was exceedingly rare. There were just two examples with B to play in almost 100,000 games. That astounded me because the joseki on the left side is/was quite common (though at 345 examples, not as common as I expected - it seems the joseki is a joseki-book favourite rather than an actual-play favourite).

So, straight away, it was impossible to test the 10 out of 10 claim, and on top of that it was wrong anyway because one pro did play the low attachment, but the other one played the attachment on top. Of course, the reasoning must have been the same so that's not a big deal. For the record, though, the pro who couldn't tell margarine from Yokota's butter was Segoe Kensaku, and - if you make what seems a reasonable assumption that White really shouldn't have got himself into the sort of position shown above - the initial "error" was by Go Seigen. Hmmm.

As indirect support for that last point about White having got himself into a dicey position, there were three examples of the above position with White to play and two of them involved amateurs.

There were several more surprises for me, but to mention just one more, White can respond to the low attachment by going into the Avalanche (nadare), i.e. trying to avoid being pushed towards thickness. In that case, Yokota recommended Black choosing a line of the small avalanche joseki. However, he did remark that it might not occur even to most young inseis because none of them seems to know this once popular joseki. And in the one example in actual play where White started the avalanche, the young Chinese player did not use (did not know?) the right line and seemed to me to get a bad result. I suppose that tells us that inseis don't read the same joseki books as us. In fact I don't think they read any joseki books - they are for amateurs. But that's another story.

For reference, in the topmost position, although White should apparently not approach high, it does seem from actual play that he can approach low. In the majority of cases Black still pushes towards the thickness, and there is just one example of a pincer. Also there are instances where White makes a point of not approaching in this area at all.

To go back to the 10 out of 10 claim, as I transcribe games daily I check Yokota's theory against actual pro play, and that has thrown up another surprise. His idea of pushing towards thickness is not new (there are other books saying the same thing - he just does it better) and so I had already registered it. But I had just registered it as one possible strategy out of several, e.g. pincering. In fact, so far, 10 out of 10 pros do seem to follow his theory and it's only amateurs who diverge.

The local decision also depends on the rest of the position. If immaterial, the move is expected.

Thanks for posting this. I've had this question for a long time about similar positions: when should you push your opponent towards your thickness and when should you give it an extension by pincering?

I generally try to decide based on the cramped-ness of the opponent's group if I just push him towards my thickness and also on the potential of my thickness cum pincer compared to playing on the other side. So in the case of your diagram I probably would not have pincered because developing the top seems not too big, that is if on the other hand the right side is still open. But I probably would agonize about wether this is right.

Yokota's reasoning/explanation that you choose your move depending on the value of the thickness is something that I find really interesting.

Without checking a database, I would assume the high approach is much rarer than the low in this position (and maybe not even going in so early in fuseki most common) because high makes it so easy for black to make good corner profit whilst pushing white towards the thickness, whereas if you want to do similar with the low approach you have to kick and your corner is smaller and weaker shape (and white has more space to extend on top). It's similar (though black top left more strong than thick, the attachment at a is a good technique after black kicks) to this one, which I seem to recall in the kisedio dictionary of fuseki korean style book:

Click Here To Show Diagram Code

[go]$$W
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . O . . X . . X a . . . . 1 . . . . |
$$ | . . . O . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

Maybe, in the AlphaGo era, if White plays on the top side this is the usual play.

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Everything with love. Stay safe.

My intuition is to play q14

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be immersed

A question of style. Both are possible.

Thanks for the points made. I have to admit, though, I was looking for something more about the psychology behind the choice. I did look at the (still valid) possibility that it was something favoured by the Honinbo school - although the first instance was due to an independent, Yamamoto Genkichi, he did study for a time with Satsugen and Honinbo-ites certainly played it a lot thereafter. I did wonder whether Yamamoto's independent status was a factor, and also whether the Honinbo school's status was, too. The Japanese teacher-pupil has long been notorious for stifling creativity in various disciplines. I'm not entirely convinced that's fair, but I was struck this morning by how conservative go players of any country can be - and I find that surprising in a competitive environment where you have to do something extra to win.



Murakami Akihide played this as his opening move yesterday (2 November 2017). I was astonished to see that this is only the second time it has appeared in the GoGoD database (the previous one was 1980, also in Japan). But then I looked at A as a first move, and was equally surprised to see it had only 18 outings (and why this move is much more popular than the "kosumi" is also perplexing).

But even tengen has appeared only 158 times, and quite a few of those can be accounted by a few people such as Kubomatsu who were researching that move.

Of course these are not the only possible oddball moves, but even across the full spectrum the frequency is tiny in a collection of almost 100,000 games. Am I right that go players are natural conservatives? Chess players often seem to be so labelled.

Compared to black’s move at ‘a’, I feel that white’s response with tengen is more painful. With black at ‘a’, if white plays tengen, black can hane. Here, if white plays tengen, it’s like black drew back.

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be immersed

Sounds good thinking to me, but in the actual games White did not play tengen or anywhere near it. The opening responses were a corner star point or a 6-4 play.

Top left black is already thick, one less argument for a pincer.

But I stay by my word, that is not worth much by the way, I think it is a matter of taste.

Maybe it’s not “conservative” but rather … scared of “the catastrophe that happened last time I tried something new”?

Reminds me of a psychological study about South Indians which I once read … what they found was that many there have a fear of trying new problem solving methods because often, when they did, something bad happened. According to the study (sorry, I forgot the source) this also leads to favouring improvised repairs of old things instead of creating new things, and as is well-known, improvisations usually hold longer than the original thing (or new things).

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Yamashita Keigo is one of the players who started with oddball openings but became more normal over time. He found it to be good early, but over long term he needed to play more 'normal' openings.

Pragmatism?

Interesting. Maybe it’s a case where pros don’t think tengen response is good, so maybe it’s some special strategy.

I dunno- maybe we can ask AlphaGo in a few years :-p

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be immersed

I am not surprised about a pro being dismissive of a pincer, since black is so strong on the upper side already. I knew I have seen this discussed recently, then I remember where: it was from Kirby's game with the Japanese ex-insei recently: viewtopic.php?p=223376#p223376
The position occurred in the lower-right in that game, during the post-game discussion, not in the actual game.
The upper-corner is different, but the idea is similar, black to play, which side to approach white's lonely stone from?



Kirby's opponent commented: "[black] is as strong as "lava', he said. So you want to push white into the lava", basically advocating that black should not approach from the upper side, but from the right side.
I found the "lava" analogy interesting.