Life In 19x19

I was wondering if someone could take a look at this game. It was one of those games where I had a very large lead in the early middle game only to find out that the lead was considerably smaller by the end of the game. I won by a comfortable margin (15.5), but I couldn't figure out where the points went!

My take is that I made three large mistakes:
1. I created a weak group on the left starting with move 37.
2. I then compounded the problem by not sacrificing the group following move 128. White gained about 15 points from attacking the running group.
3. Move 197 was just terrible shape that gave white another 10 points.

Additionally, I wasn't sure about move 71:

Click Here To Show Diagram Code

[go]$$c
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . X . . . . . . . X . . O X . |
$$ | . O . X . . . . . X . . . . X X O X . |
$$ | . . . . . . . . . . . . . X O O X X . |
$$ | . . O . c . . . . . . . . X O O O O . |
$$ | . . . . . . . . . . . b . O . O . . . |
$$ | . . . O . . . . . . . . . . O . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . , . . . . a , X . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X . . . . . . . . . . . . . . . X . |
$$ | . O O O O . . . . B . . . . O O O O . |
$$ | . X X X O X . . . . . . . X O X X X . |
$$ | . O O O X . X . . . . . X . X O O O . |
$$ | . . . . . X . . . . . . . X . . . . . |
$$ +---------------------------------------+[/go]

To me there are two issues here. First, I do not have a good sense of how strong the ponnukis on the bottom are. My best guess is that white could deny one of those two a base and force it to run. The second issue is that the group on the left is weak. So, white could play two weak groups against each other. This was my rationale for the move I chose. A-C were also options, and now that I Think about it, playing another move on the left to settle that group is also possible.

Here is the full game:

Quick reply: from position 71 I would never think B+15,5
I would even prefer white

@Knotwilg: I would be interested in how you evaluate the position at move 71.

For Black I see about 15 points at the bottom and 30 points at the top (supposing that White will invade at H17).

For White I see about 16 points at the top left, 11 points at the bottom left and 11 points at the bottom right.
So Black has a small lead (certainly smaller than 15.5 points) but has more weak groups than White.

Some comments:
- Having the two ponnukis facing each other isn't too bad, but a bit awkward: if you grow one side with f4 then white reduces other side at n5.
- Rather than bottom left 3-3 I would prefer f3 approach, if white sensible c6 answer then o4 push makes a good lower side formation you will often see in bot games. In fact it's so nice white will sometimes n5 knight move to prevent it and allow the double approach.
- You have a bad habit of playing b5/s5. This is not the good forcing move from this direction, it's b6/s6.
- But it's probably aji keshi to make those exchanges anyway because by forcing white to capture the 3 stones you lose power of f4/o4 pushes (white can't double hane, and if ignore e5/p5 is sente. This would grow the lower side in an efficient and large way.
- So b5 and s5 made your ponnukis weaker but gained little on the sides.
- k4 plonking in the middle makes it too easy for white to reduce from both sides and make it inefficient.

Click Here To Show Diagram Code

[go]$$c
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . X . d . . . . . X . . O X . |
$$ | . O . X . . . . . X . . d . X X O X . |
$$ | . . . . . . . . . . . . . X O O X X . |
$$ | . . O . . . . . . . . . . X O O O O . |
$$ | . . . . . . . . . . . . . O . O . . . |
$$ | . . . O . . . . . . . . . . O . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . , . . . . b , X . . |
$$ | . . X . . . . . . . . . . . . . . b . |
$$ | . . . . c . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . X . . |
$$ | . c . . . . . . . . . . . . . . . . . |
$$ | . X . . . . . . . . . . . . . . . X . |
$$ | . O O O O . . . . X . . . . O O O O . |
$$ | . X X X O X . a . . . a . X O X X X . |
$$ | . O O O X . X . . . . . X . X O O O . |
$$ | . . . . . X . . . . . . . X . . . . . |
$$ +---------------------------------------+[/go]

My positional judgment

By symmetry, White has 20 points at the bottom and two rock solid groups facing sides and centre. The upper left is less solid but can be counted as some 15 points. Add komi and White has 40+ points

Black has 10+ at the bottom and 20 something in the top right. The stones on the left side and the right side are essentially weak groups, but I'm willing to grant at least one of them 5 points. The top is a moyo of 20 points and by that token should be counted as 10.

That gives Black 45 points so, as JLT says, the territory balance is tilted slightly in Black's favor.
If we look at the strength balance however, I find it's heavily tilted in White's favor. Its weakest group its the somewhat bizarre ponnuki-with-lump and it's not weak. Black on the other hand:
- must take the shape poking a-moves into account
- can be capped and undercut on the right side by the b-moves
- similarly on the left side by the c-moves
- and can be invaded and poked at in his moyo by the d-moves

And it's White to move now.

So, if White, from this favorable position, has lost by 15,5 then she has probably not "used thickness to attack". (Need to look at the game still)

And from this analysis, I don't agree with the OP Blindgroup that Black had a "very large lead in the early middle game"

EDIT: I now see that komi is 0,5

That changes things quite a bit. I still favor White (I like to have thickness) but the advantage is less outspoken.

Knotwilg wrote:Quick reply: from position 71 I would never think B+15,5
I would even prefer white

That's what I love about this game! Just when you think you are starting to get a handle on it, something like this reminds you that you really don't understand the game at all

I feel like did in graduate school when I'd go to my advisor with a "brilliant" idea only to be told, "Well, that obviously won't work for these five reasons that you should have aware of!". You immediately realize that the world is even more beautifully complex than you had understood. But like graduate school, if you just keep banging your head against the wall, it eventually starts to crack. Just takes a lot of effort and pain before it does.

Come to think of it, that's probably why this game is not very popular!

That said, thanks for the feedback. Been trying out these new AI fuseki moves largely because I feel like I don't understand them at all. Starting to get a sense of what I don't understand. I've had the feeling that one of my issues is that I'm not seeing the board correctly at the start of the middle game, and this supports that. Slowly, the "unknown unknowns" are becoming "known unknowns".

Several comments. As always, no guarantees.

Main focus: Neglect of the center.

Black neglected the center after White 122. I know, the center magari for Black 123 does not look like much, but center magaris are bigger than they look, as a rule, and it plainly was big enough to make eye shape, even with the White wall nearby. Later on, when White attacked the Black group on the left, expanding into the center was the easiest way to make life. There is a rule of thumb, attributed to Murase Shuho by Korschelt, One eye plus access to the center. In this case it was not clear that Black had more than a half eye on the side, but the center was inviting. That rule of thumb applies even early in the game.

But generally speaking, in the middle game the center begins to became increasingly important, and is usually prominent by move 100 or so. (See https://senseis.xmp.net/?PointPopularityByMoveNumber .) So it should be normal to look for life in the center at moves 127 and 135.

Another focus: Do not approach the opponent's strength. In this game Black made a base close to the opponent's strong wall on both the right and left sides. This was the cause of problems later on. In fact, top human players, as well as bots, will often choose to jump towards the center rather than make a base close to the opponent's strong wall, even though the opponent may choose to prevent a base after the jump. This often happens in the opening.

Yet another focus: Combining attack and defense. In this game each player had the opportunity to make a play on the side which would make eye shape for himself and take away potential eye shape from the opponent. Those are normally big plays. Moi, I did not learn about such plays until I was a dan player, but their importance is useful knowledge, and, once you are aware of it, not very difficult to spot.



BTW, you ask where did the points go. Well, I suppose, Black had some potential in the center to top left, but White made territory there in the attack against Black's left side group.

Bill Spight wrote:Several comments. As always, no guarantees.

Bill, thanks as always for the detailed comments. Your and Uberdude's comments about S6 and B6 instead of S5 and B5 were very helpful. I'd never played these moves before, but recalled them from a Lizzie review from a few months ago. Seems I didn't remember the sequence correctly. Bigger question, OC, is why I didn't immediately see my mistake and the correct move...

Two questions from your comments:

1. Here you recommend A instead of B due to the white wall. I played B to limit the value of the wall's influence. I'll also confess I *think* that I'm following Dwyrin's recommendation here in that he often plays moves like this when white has a wall in the area of this wall. But like with Lizzie, I could have easily misunderstood. Does A have a similar utility to B in this case that I don't see? I feel like I'm missing something, but don't see it clearly enough to formulate a question.

Click Here To Show Diagram Code

[go]$$c
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , b . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O O . . . . , . . . . O O O . . |
$$ | . . X X O X . . . . . . . X O X X . . |
$$ | . . O O X . X . . . . . X . X O O . . |
$$ | . . . . . X . . . . . . . X . . . . . |
$$ +---------------------------------------+[/go]

2. I do not understand this move. I see that it extends black's group on the right further into the center, but since black can make life on the side, I'm guessing that there is some larger strategic value here. I kind of see that this exerts control over the triangle area, but to me, white's triangle stones would seem to make building territory there hard.

Click Here To Show Diagram Code

[go]$$c
$$ +---------------------------------------+
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . . O . O X X X . . . . . . . . . . |
$$ | . . O . O X . O X . . X . X . . O X . |
$$ | . O . X . X . O O X X . X . X X O X . |
$$ | . . . . . . . . X O O X O X O O X X . |
$$ | . . O . . X . . X . O . O X O O O O . |
$$ | . . . . . . . . . X . O . O . O . . . |
$$ | . . . O . . . . . . X O O . O . . . . |
$$ | . . O . . . . . . . . O X . . . . O . |
$$ | . . X O . . . . . X . X X . X X X . . |
$$ | . . X . . . . . . . . . . . Q Q X . . |
$$ | . . . . . . . . . T T T . . Q X . . . |
$$ | . . X . . . . . . . . . . . Q X X X . |
$$ | . . . . . . . . . . . . . . Q . . O . |
$$ | . X . . . . . . . . . . . . . . O X . |
$$ | . O O O O . . . . X . . O . O O O O . |
$$ | . X X X O X . . . . . X . X O X X X . |
$$ | . O O O X . X . . . . . X . X O O O . |
$$ | . . . . . X . . . . . . . X . . . . . |
$$ +---------------------------------------+[/go]

Uberdude wrote:You have a bad habit of playing b5/s5. This is not the good forcing move from this direction, it's b6/s6.

Thanks. Definitely a case of "right idea, wrong move", modulo the aji keshi, OC.

Uberdude wrote:Rather than bottom left 3-3 I would prefer f3 approach, if white sensible c6 answer then o4 push makes a good lower side formation you will often see in bot games. In fact it's so nice white will sometimes n5 knight move to prevent it and allow the double approach.

I like this sequence, and had not seen it before. Does it continue like this? And if so, how far does white push? Also, presumably A and B are also big, but I confess that I'm struggling to understand when to play them in other similar formations. In this case, it seems like B does much of the work of A given the distance between F3 and the wall.

Click Here To Show Diagram Code

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

BlindGroup wrote:

Bill Spight wrote:Several comments. As always, no guarantees.

Bill, thanks as always for the detailed comments. Your and Uberdude's comments about S6 and B6 instead of S5 and B5 were very helpful. I'd never played these moves before, but recalled them from a Lizzie review from a few months ago. Seems I didn't remember the sequence correctly. Bigger question, OC, is why I didn't immediately see my mistake and the correct move...

Two questions from your comments:

1. Here you recommend A instead of B due to the white wall. I played B to limit the value of the wall's influence. I'll also confess I *think* that I'm following Dwyrin's recommendation here in that he often plays moves like this when white has a wall in the area of this wall. But like with Lizzie, I could have easily misunderstood. Does A have a similar utility to B in this case that I don't see? I feel like I'm missing something, but don't see it clearly enough to formulate a question.

$$c
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . . . . c . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , b . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O O . . . . , . . . . O O O . . |
$$ | . . X X O X . . . . . . . X O X X . . |
$$ | . . O O X . X . . . . . X . X O O . . |
$$ | . . . . . X . . . . . . . X . . . . . |
$$ +---------------------------------------+

Click Here To Show Diagram Code

[go]$$c
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . . . . c . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , b . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O O . . . . , . . . . O O O . . |
$$ | . . X X O X . . . . . . . X O X X . . |
$$ | . . O O X . X . . . . . X . X O O . . |
$$ | . . . . . X . . . . . . . X . . . . . |
$$ +---------------------------------------+[/go]

Well, the bots like "a". But my understanding goes back to Sakata and Takagawa.

Takagawa in relation to "b". White's wall in the bottom right is alive in itself and does not require an extension on the right side. (The bots go further, often not extending from weaker walls.) My corollary: If White is not going to extend to "b", why should Black play there to prevent it. The idea that Black "b" "kills" the White influence is an amateur myth.

So in similar situations I used to play "c". In one of his books Sakata mentioned that "a" was also possible, in line with not approaching the opponent's strength. Since then "a" has become more popular than "c", not considered an extension so much as an enclosure. It is definitely more solid. Even after Black "a" White can approach the top right corner from the right side -- after "c" White freely approaches the corner from the right side, and after "b" White often invades --, so the right side is not exactly no man's land in the opening, but it is not exciting at this point. Furthermore, the Black enclosure with "a" exerts influence on the top side, working with the top left stone.

2. I do not understand this move. I see that it extends black's group on the right further into the center, but since black can make life on the side, I'm guessing that there is some larger strategic value here. I kind of see that this exerts control over the triangle area, but to me, white's triangle stones would seem to make building territory there hard.

$$c
$$ +---------------------------------------+
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . . O . O X X X . . . . . . . . . . |
$$ | . . O . O X . O X . . X . X . . O X . |
$$ | . O . X . X . O O X X . X . X X O X . |
$$ | . . . . . . . . X O O X O X O O X X . |
$$ | . . O . . X . . X . O . O X O O O O . |
$$ | . . . . . . . . . X . O . O . O . . . |
$$ | . . . O . . . . . . X O O . O . . . . |
$$ | . . O . . . . . . . . O X . . . . O . |
$$ | . . X O . . . . . X . B X . X X X . . |
$$ | . . X . . . . . . . . . . . Q Q X . . |
$$ | . . . . . . . . . T T T . . Q X . . . |
$$ | . . X . . . . . . . . . . . Q X X X . |
$$ | . . . . . . . . . . . . . . Q . . O . |
$$ | . X . . . . . . . . . . . . . . O X . |
$$ | . O O O O . . . . X . . O . O O O O . |
$$ | . X X X O X . . . . . X . X O X X X . |
$$ | . O O O X . X . . . . . X . X O O O . |
$$ | . . . . . X . . . . . . . X . . . . . |
$$ +---------------------------------------+

Click Here To Show Diagram Code

[go]$$c
$$ +---------------------------------------+
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . . O . O X X X . . . . . . . . . . |
$$ | . . O . O X . O X . . X . X . . O X . |
$$ | . O . X . X . O O X X . X . X X O X . |
$$ | . . . . . . . . X O O X O X O O X X . |
$$ | . . O . . X . . X . O . O X O O O O . |
$$ | . . . . . . . . . X . O . O . O . . . |
$$ | . . . O . . . . . . X O O . O . . . . |
$$ | . . O . . . . . . . . O X . . . . O . |
$$ | . . X O . . . . . X . B X . X X X . . |
$$ | . . X . . . . . . . . . . . Q Q X . . |
$$ | . . . . . . . . . T T T . . Q X . . . |
$$ | . . X . . . . . . . . . . . Q X X X . |
$$ | . . . . . . . . . . . . . . Q . . O . |
$$ | . X . . . . . . . . . . . . . . O X . |
$$ | . O O O O . . . . X . . O . O O O O . |
$$ | . X X X O X . . . . . X . X O X X X . |
$$ | . O O O X . X . . . . . X . X O O O . |
$$ | . . . . . X . . . . . . . X . . . . . |
$$ +---------------------------------------+[/go]

Yeah, this is not easy to understand. It helps to have experience with turns and in particular with central turns. Even turns on the third and fourth lines did not seem that big to me as an SDK, but, having read that they were good, I tried them out in my own games and was pleased with the results. Central turns are also surprisingly big, even in the opening. I saw them in games by players like Fujisawa Hideyuki (AKA Shuko), Go Seigen, and Takagawa.

Yes, Black made small life on the right side, but small life is an unworthy goal as a rule, even after move 100. Korschelt was the second go book I owned (the first being Lasker), so even as a triple digit kyu I followed the one eye and access to the center rule of thumb and had a lot of experience making life in the center. So to me was kind of obvious. But that really relies upon my experience, more or less summed up with "bigger than it looks" and "easy life".

As for territory, suppose that White had a stone at . Then Black on the right would be scrambling for life and Black's potential for territory in the center would be greatly reduced, not only towards the bottom side, but also towards the upper left.

From your play and comments it is plain that you think of making life on the side. But Murase Shuho (and I) say, don't forget the center.

Edit: I should add, I have a lot of experience with not making life in the center.

Turns are the best. I recommend that whenever you make one, for the rest of the game, you should occasionally look back at it and sigh contentedly, and for any nearby sequence where it makes a difference (there will probably be a lot of them), grin broadly as you realize that you have the upper hand because your local position is so strong. We are so used to being told to play lightly and flexibly that we forget how good it is to play strongly in places where it matters.

dfan wrote:Turns are the best. I recommend that whenever you make one, for the rest of the game, you should occasionally look back at it and sigh contentedly, and for any nearby sequence where it makes a difference (there will probably be a lot of them), grin broadly as you realize that you have the upper hand because your local position is so strong. We are so used to being told to play lightly and flexibly that we forget how good it is to play strongly in places where it matters.

I think you and Bill are right. I'm just going to have to play this move when I see the chance and see how it works in practice

Bill Spight wrote:Well, the bots like "a". But my understanding goes back to Sakata and Takagawa.

Takagawa in relation to "b". White's wall in the bottom right is alive in itself and does not require an extension on the right side. (The bots go further, often not extending from weaker walls.) My corollary: If White is not going to extend to "b", why should Black play there to prevent it. The idea that Black "b" "kills" the White influence is an amateur myth.

So in similar situations I used to play "c". In one of his books Sakata mentioned that "a" was also possible, in line with not approaching the opponent's strength. Since then "a" has become more popular than "c", not considered an extension so much as an enclosure. It is definitely more solid. Even after Black "a" White can approach the top right corner from the right side -- after "c" White freely approaches the corner from the right side, and after "b" White often invades --, so the right side is not exactly no man's land in the opening, but it is not exciting at this point. Furthermore, the Black enclosure with "a" exerts influence on the top side, working with the top left stone.

So, if I understand you correctly, the move in the following diagram would be a good one, but not because it mitigates influence. Rather, white needs to extend from the wall in order to make a base, and black's move constrains the impending extension. An example of my opponent's best move being my best move.

Diagram 1

Click Here To Show Diagram Code

[go]$$c
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , B . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O O . . |
$$ | . . . . . . . . . . . . O O O X X . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

That makes sense to me in this case, but what about in this slightly different (admittedly slightly contrived) variation. Here white has a larger, stronger wall because of incorrect play by black. In this case, is the logic that white is already alive and this should dictate your suggested move at A, since white R10 is not necessary for white to live? Or does the larger wall make R10 now a big enough move for white that it makes sense for black to play there instead of A?

Diagram 2

Click Here To Show Diagram Code

[go]$$c
$$
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , B . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O O . . |
$$ | . . . . . O . . O O O O O O O X X O . |
$$ | . . . . . . . . . X X X X X X X O . . |
$$ | . . . . . . . . . . . . . . . . . O . |
$$ +---------------------------------------+[/go]

BlindGroup wrote:

Bill Spight wrote:Well, the bots like "a". But my understanding goes back to Sakata and Takagawa.

Takagawa in relation to "b". White's wall in the bottom right is alive in itself and does not require an extension on the right side. (The bots go further, often not extending from weaker walls.) My corollary: If White is not going to extend to "b", why should Black play there to prevent it. The idea that Black "b" "kills" the White influence is an amateur myth.

So in similar situations I used to play "c". In one of his books Sakata mentioned that "a" was also possible, in line with not approaching the opponent's strength. Since then "a" has become more popular than "c", not considered an extension so much as an enclosure. It is definitely more solid. Even after Black "a" White can approach the top right corner from the right side -- after "c" White freely approaches the corner from the right side, and after "b" White often invades --, so the right side is not exactly no man's land in the opening, but it is not exciting at this point. Furthermore, the Black enclosure with "a" exerts influence on the top side, working with the top left stone.

So, if I understand you correctly, the move in the following diagram would be a good one, but not because it mitigates influence. Rather, white needs to extend from the wall in order to make a base, and black's move constrains the impending extension. An example of my opponent's best move being my best move.

Diagram 1

$$c
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , B . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O O . . |
$$ | . . . . . . . . . . . . O O O X X . . |
$$ | . . . . . . . . . . . . b X X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+

Click Here To Show Diagram Code

[go]$$c
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , B . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O O . . |
$$ | . . . . . . . . . . . . O O O X X . . |
$$ | . . . . . . . . . . . . b X X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

I didn't mean to say that extensions such as the one on the right do not mitigate influence. They certainly can. And that would be the main reason to play it here. Before the bot era humans used to play the hane-and-connect, in which case the extension was too close. Edit: For that reason, is probably not good, because White "b" will force Black to live in the corner, and will be too close to White's strength. So Black should extend to "b", as the bots have taught us.

Edit 2:

Click Here To Show Diagram Code

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

After the second line extension and White's reply, I note that Deep Leela (Leela 11) prefers to "a", but within its margin of error.

That makes sense to me in this case, but what about in this slightly different (admittedly slightly contrived) variation. Here white has a larger, stronger wall because of incorrect play by black. In this case, is the logic that white is already alive and this should dictate your suggested move at A, since white R10 is not necessary for white to live? Or does the larger wall make R10 now a big enough move for white that it makes sense for black to play there instead of A?

Diagram 2

$$c
$$
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , B . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O O . . |
$$ | . . . . . O . . O O O O O O O X X O . |
$$ | . . . . . . . . . X X X X X X X O . . |
$$ | . . . . . . . . . . . . . . . . . O . |
$$ +---------------------------------------+

Click Here To Show Diagram Code

[go]$$c
$$
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , B . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O O . . |
$$ | . . . . . O . . O O O O O O O X X O . |
$$ | . . . . . . . . . X X X X X X X O . . |
$$ | . . . . . . . . . . . . . . . . . O . |
$$ +---------------------------------------+[/go]

In this case, Black "a" is probably fine, IMO. However, White's wall is so huge that it is not practical to avoid it entirely. That being the case may be OK. You have to approach it sooner or later, why not now?

Edit 3: I set up this position with Deep Leela, and it now prefers to "a", again within its margin of error. But that has to do with other things besides the White wall.

Click Here To Show Diagram Code

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

If we just extend the wall to here, is still its preferred move.

Click Here To Show Diagram Code

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

Extend the wall by one more stone and it's preferred move changes to this one. Leela 11 does not in general like to approach strong stones. (OC, Leela 11 is no longer a top bot.)

----
Before the bot era I was fairly confident about such things, as I have a thick style of play. But the top bots' sense of the center is so advanced that I am not sure of much. Many plays that I think of as thick are surely heavy.