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.

NB please, especially if your initials are RJ, do not judge Sonoda's theory on my extracts here - read the whole book first. It is packed with gold nuggets like this, mostly on PJ but his views on running fights alone are worth the cost of the book.

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?

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.

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It seems to me that the Black groups are alive in the ordinary sense that each one can survive by responding to an attack. They are not alive in the sense of already having two eyes. I wonder what Sonoda would have to say about the Possible Omission Number.



No quarrel there. However, I find it hard to think that he does not regard the group as thick for the dual purpose of attacking the orphan White stone and providing safety for the orphan Black stone.



IIUC, Wilcox's theory says to play the one space jump (another diagonally related play) because it cuts the sector line between the White stone on L-04 and the White stone on R-06, which N-04 does not do. However, the jump lets White play a peep, which strengthens the White orphan, and N-04 threatens to connect underneath to the Black group to the left.

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

Visualize whirled peas.

Everything with love. Stay safe.

Was the iceberg shape this one?

Click Here To Show Diagram Code

[go]$$c
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . O . . X . . X . O . O O . . |
$$ | . . . O . . . . . , . . . . X X X . . |
$$ | . . . . . . . . . . . . X . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . W X X X . . |
$$ | . . . . . . . . . . . . W . W X W . . |
$$ | . . . O . . . . . , . . . W W W W . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . X . . X , . . . . . , X . . |
$$ | . . O X X . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

If so, I think that the iceberg shape above is a lot more thick than the example in this thread:
1. White's stones are solid without defects.
2. White has good shape for eyes.
3. White has a "foothold" on the side of the board, which gives it strength compared to something floating.

The example given is not exactly weak, but the shape isn't as good IMO, and the connection to the right side stones is thin.

That being said, I wouldn't say black's group in this thread is really weak, either. But maybe on the scale of "thickness", less than the iceberg shape, IMO.

_________________
be immersed

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.

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

Visualize whirled peas.

Everything with love. Stay safe.

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.

OK, thanks.

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

Visualize whirled peas.

Everything with love. Stay safe.

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.

All stones exert influence. Only a few have thickness. So it's not a matter of better. The main step is to make a clean distinction - as you have done.

The problem area, apart from misguided use of terms (which is to a large degree a legacy of poor translations in the early days), is that too many people think lots of influence = thickness. Some people get over that but then the second problem is making shapes they think are thick but aren't (because of lack of eye shape or forcing moves).

Part of the debates we've been having here might be seen as the next stage beyond that - shapes that we think are thick, taking into account possible eyes and possible forcing moves, may not be thick to a pro.

Apart from that aspect, which only a pro can comment on, I imagine, another, separate plank of my argument is that the test for such shapes should not be limited to eyes and forcing moves but whether or not the shape can function as thickness. Not only did I believe that when I first broached that topic, I see it is now confirmed by the Sonoda book I have been commenting on. There is a stage beyond that, however. Dan players can easily see how thickness can be used for attacks, or for less common uses such as a refuge for running groups. But only pros seem to have a good instinct for how thickness will also help them in the endgame. I can see after the event that this happens but I rarely have any real sense of how and when they make the appropriate moves early in the game, although one of the new books did reveal it was something to do with the type of connections.

Sonoda's diagonal and tate (orthogonal) lines.

Sonoda is not all that clear about the difference between the two in what I have read. He points out that to make a single point eye requires stones that are on diagonally related lines. Other nearby points, those that are adjacent to a stone or make a keima with it, may not be necessary. He generalizes the diagonal relationship to more distant stones, that is clear. And stones on other points are related by "tate" lines.

Examples:

Click Here To Show Diagram Code

[go]$$c Diagonal line
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . X . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . O O . X . . X , .
$$ | . . O X X . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ -----------------------
$${AR J4 H5}
$${AR H5 J6}
$${AR J6 H7}[/go]

Click Here To Show Diagram Code

[go]$$c Tate line
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . X . . .
$$ | . . . . . . . . . . .
$$ | . . O O . X . . X , .
$$ | . . O X X . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ -----------------------
$${AR J4 H5}
$${AR H5 H6}[/go]

But he also gives the example of a one space jump, and says that both ways apply. You can consider the two stones to be connected by both kinds of lines.

Click Here To Show Diagram Code

[go]$$c Two way line
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . X . .
$$ | . . . . . . . . . . .
$$ | . . O O . X . . X , .
$$ | . . O X X . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ -----------------------
$${AR J4 H5}
$${AR H5 J6}
$${AR J4 J5}
$${AR J5 J6}[/go]

However, any two stones connected along a diagonal line can also be connected along an orthogonal line, so there is some ambiguity. Here is a possible way to resolve the ambiguity while retaining it for the one space jump. Take the shortest path between stones as the defining one. If there is a path that uses only diagonal lines and is shorter than all rook-wise paths, then the stones are considered only diagonally related. The only ambiguous cases are odd spaced jumps in a straight line.

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

Visualize whirled peas.

Everything with love. Stay safe.