Sonoda also has interesting things to say about tactics. One applicable here is that when you have more stones than your opponent you use them orthogonally and if you have fewer you use them diagonally (there is also separate advice to "cut the opponent's diagonals"). Hence the right move here for Black is N4.

I guess N4 is a diagonal? So black is outnumbered because there are 3 (or 4?) white stones nearby, and that outweighs the fact that white's L4 is surrounded by 2 black stones?

What would the orthogonal move be, one space jump to O5?

There was a thread recently in which I queried whether a shape that others saw as thick (i.e. good) was really potentially weak to a pro's eyes. I couldn't prove it, of course, but said it reflected my observations that pros typically cast aspersions on the strength of groups far earlier than we do, sometimes apparently with x-ray eyes. I had to take quite a bit of stick, even though I was just reporting an impression.

I came across yet another example today, and in some respects it was remarkably similar to Iceberg. It may illustrate why I get this impression.

This was the position:



The context is Sonoda Yuichi demonstrating (in his book I mentioned in the "Slew of books" thread) how to perform positional judgement throughout a game. This was a game of his with Honda Kunihisa.

I'm going to have to omit a lot of the background to his PJ approach, but essentially it consists in establishing the current conditions in terms of a short series of criteria, one of which is to establish which areas still have stones that are not alive. This is applied to the right and lower portions of the current position because of a couple of other criteria I am omitting to do with attacking.

Now, judging by the comments in the iceberg thread, there will be people here who point to the centre Black group as thickness and will say that it is alive (one eye on the side, etc.).

But Sonoda's assessment of areas where stones are not alive is: "Black's group in the centre, Black's group on the lower side, White's single stone on the lower side and Black's single stone on the lower side."

Nowhere does Sonoda refer to this central Black group as thickness, even earlier in the game when this central position was being formed. Equally, he does not specifically say it is weak - he just says it is not alive (though since that is used as a criterion for deciding subsequent strategy, some sort of potential defectiveness is being implied). When the shape was formed, he simply said of Black's play that he had no reason to be dissatisfied, and in the immediate lead-up to the current position he makes a reference to a growing Black moyo from the left side to the centre.

In a nutshell, I think Sonoda is making a different assessment of this group than people here (including me) would make.

Sonoda also has interesting things to say about tactics. One applicable here is that when you have more stones than your opponent you use them orthogonally and if you have fewer you use them diagonally (there is also separate advice to "cut the opponent's diagonals"). Hence the right move here for Black is N4.

The one space jump is considered to have a diagonal connection to the original stone, because it can be reached in two diagonal moves. Sonoda's theory is consistent with the proverb, one space jump for defense.

Ok so an orthogonal move would be a knights move to N5 or an iron pillar to O4?

No, I don't think so. I'm using orthogonal for tate-yoko (and naname is diagonal).

Bill's mention of diagonal move for defence seems inappropriate here as it is being used for attack (despite Black having fewer stones in that specific area).

Also, I've mentioned before that Wilcox's sector line theory can be pre-dated to Japan (e.g. Miyamoto) and Sonoda seems to be using the same theory, but until I go through the book fully I'm not yet certain if that's his intent (if it is, he's also expanding the theory anyway).

Also, note that I carefully said "use" and not "play" stones orthogonally/diagonally, following Sonoda. That may include stones already on the board. I'm again not yet certain if he's thinking that broadly. He's precise about his terms, and what I've seen so far about go theory is so startling that it forces your mind to stay open to such possibilities. But I'm just dipping in and out of the book at various points on train rides, etc., so I may be missing crucial comments.

PS Note that this is yet more PJ with no counting of territory. It's not just a trend now, it's a landslide

Ok then I'm out of guesses for what the orthogonal move would be for this example. Does the book say?

I think it was Bill that already said it, O5.

IIUC, O-05 is also a diagonally related move, according to Sonoda's theory. I'll look it up again

Yes, this is possible, but I think he may be making two quite separate points: playing ON a diagonal and cutting a diagonal (i.e. a sector line). As I've said, until I read all the book and in the right order, I'll remain hazy on that. Unfortunately, in this particular cases, he uses both usages (naname ni ishi o tsukau AND aite no naname no rain o kiru). together. Despite what I said about him seeming precise in his use of terms, I haven't spotted a definition of what he means by naname no rain; the examples point strongly to sector line, but I stress that that so far is just my interpretation.

John, am I understanding you right that you are interested in getting us to make a better distinction between thickness and influence? That is, the stones in your example surely can be said to exert influence, but whether they are thickness is debatable.