Life In 19x19

Posted: **Wed Aug 30, 2023 5:51 am**

Click Here To Show Diagram Code: [go]$$B Moves 97 to 97 $$ --------------------------------------- $$ | . . . . . . . . . . . O X X . . . . . | $$ | . . . . . . . . . . . . O X . X . . . | $$ | . . . . O O . . . . . O . O X . . . . | $$ | . d O O . X O O . , . . . O . X . . . | $$ | . O X X . X X X O . O . . O . . . . . | $$ | . X . . . . . 1 X O . . . . . X . . . | $$ | . . . X c . . . X . . . . . O X . . . | $$ | . . . X O O O O . . . . . . . . . . . | $$ | . . . O X X O X . . . . . O . X . . . | $$ | . . X X X O . O . , . . . . . , X . . | $$ | . . . . . X O . . . . . . b . O X . . | $$ | . . . . O O O . . . . . . . . . . . . | $$ | . . O . O X X X . . . . . . O O O . . | $$ | . . . O X X . . . . . . . . . X X . . | $$ | . . . X . O . . . . . . . . . . . . . | $$ | . . X , . X . . . , . . . . . X . . . | $$ | . . X O X X O . . O . . O . X . . . . | $$ | . . O . X O O . . . . . . a . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

was an almost inexplicable move by Takagawa. Visually alone, the double empty triangle is almost too ugly to bear. Now, in fights or otherwise, sometimes the empty triangle is "good shape". Here however, the only value is saving the two stones and neutralizing the empty space behind it. Even a simple endgame move like A is visibly bigger. The center can be reduced while attacking the right side, with a move like B. Even turning at C protects the two stones with better shape. And then there's D.

At that point, Black was leading by 13+ points. Was it a declaration of victory?

Posted: **Wed Aug 30, 2023 9:27 am**

Knotwilg wrote: I don't actually believe in it myself but I thought trying it out is a more interesting expenditure of my time than trying to convince someone verbally. Unfortunately we haven't seen the OP yet participate in this spin-off.

If that's me, I'm following. Haven't had time for much more since about Saturday. Kids and I are down with a cold and I had previous RL commitments.

Take care.

Posted: **Wed Aug 30, 2023 10:07 am**

Knotwilg wrote: was an almost inexplicable move by Takagawa. [...]

Knotwilg wrote:At that point, Black was leading by 13+ points. Was it a declaration of victory?

It is not obvious to me that black would want to play a or b (maybe that is supposed to be the attachment?). White needs points in the center and what often happens when you need to make points somewhere is that this becomes a weakness. A weakness that you must defend for a long time or forgo the chance to make more points. The strategic imperative in this position appears to be to exploit white's territory ambition in the center.

White does respond to the "almost inexplicable" move after playing one sente move elsewhere. I don't think that makes it 9 points sente, equal to 18 points gote, the territory doesn't really change that much overall. It is also not precises values that are most important, instead it is the strategic dimension. Connecting solidly appears to allow black to aim to pull out that one stone (there could be a ko) or at least have a much stronger anchorage in the center. That will matter if white doesn't respond. Possibly white is out of options as he keeps building the center and doesn't this demonstrate that connecting was good?

Of course it matters that black is ahead.

Posted: **Wed Aug 30, 2023 11:45 am**

kvasir wrote: It is not obvious to me that black would want to play a or b (maybe that is supposed to be the attachment?). White needs points in the center and what often happens when you need to make points somewhere is that this becomes a weakness. A weakness that you must defend for a long time or forgo the chance to make more points. The strategic imperative in this position appears to be to exploit white's territory ambition in the center.

Thx. I didn't merely use AI to spot this "mistake". I just couldn't guess Black's move 97 and when I saw it, I was surprised. I understood the meaning as you explained it but I couldn't see how it was bigger than any of the side moves. And when KataGo pointed it out as the major mistake in the game, I saw that as a confirmation of my doubts. It's rare for me to spot a pro mistake so I thought, maybe it was a declaration of victory? "Look, I can play this suboptimal move and still comfortably win?"

Click Here To Show Diagram Code: [go]$$B Moves 97 to 97 $$ --------------------------------------- $$ | . . . . . . . . . . . O X X . . . . . | $$ | . . . . . . . . . . . . O X . X . . . | $$ | . . . . O O . . . . . O . O X . . . . | $$ | . d O O . X O O . , . . . O . X . . . | $$ | . O X X . X X X O . O . . O . . . . . | $$ | . X . . 8 6 4 2 X O . . . . . X . . . | $$ | . . . X 9 7 5 3 X . . . . . O X . . . | $$ | . . . X O O O O . . . . . . . . . . . | $$ | . . . O X X O X . . . . . O . X . . . | $$ | . . X X X O 1 O . , . . . . . , X . . | $$ | . . . . . X O . . . . . . b . O X . . | $$ | . . . . O O O . . . . . . . . . . . . | $$ | . . O . O X X X . . . . . . O O O . . | $$ | . . . O X X . . . . . . . . . X X . . | $$ | . . . X . O . . . . . . . . . . . . . | $$ | . . X , . X . . . , . . . . . X . . . | $$ | . . X O X X O . . O . . O . X . . . . | $$ | . . O . X O O . . . . . . a . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

I could NOT see KataGo's recommendation but upon seeing it, I can immediately understand it: if

cuts, then

at the end of a foreseeable sequence is atari on the stones below. I would think Takagawa can see that too and appreciate it as more elegant and more valuable than the original move.

Click Here To Show Diagram Code: [go]$$B Moves 97 to 97 $$ --------------------------------------- $$ | . . . . . . . . . . . O X X . . . . . | $$ | . . . . . . . . . . . . O X . X . . . | $$ | . . . . O O . . . . . O . O X . . . . | $$ | . b O O . X O O . , . . . O . X . . . | $$ | . O X X . X X X O . O . . O . . . . . | $$ | . X . . . . . . X O . . . . . X . . . | $$ | . . . X . . . . X . . . . . O X . . . | $$ | . . . X O O O O . . . . . . . . . . . | $$ | . . . O X X O X 2 . . . . O . X . . . | $$ | . . X X X O 1 O . , . . . . . , X . . | $$ | . . . . . X O a . . . . . . . O X . . | $$ | . . . . O O O . . . . . . . . . . . . | $$ | . . O . O X X X . . . . . . O O O . . | $$ | . . . O X X . . . . . . . . . X X . . | $$ | . . . X . O . . . . . . . . . . . . . | $$ | . . X , . X . . . , . . . . . X . . . | $$ | . . X O X X O . . O . . O . X . . . . | $$ | . . O . X O O . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

If White responds here then Black has gained already and there's new aji at A. I would still play elsewhere now (B) and accept the loss of 4 stones for a squeeze and more sente (next diagram). Should check again what KG says here.

Click Here To Show Diagram Code: [go]$$B Moves 97 to 97 $$ --------------------------------------- $$ | . . . . . . . . . . . O X X . . . . . | $$ | . . . . . . . . . . . . O X . X . . . | $$ | . 2 . . O O . . . . . O . O X . . . . | $$ | . 1 O O . X O O . , . . . O . X . . . | $$ | 3 O X X . X X X O . O . . O . . . . . | $$ | . X . . 0 8 6 4 X O . . . . . X . . . | $$ | . . . X . 9 7 5 X . . . . . O X . . . | $$ | . . . X O O O O . . . . . . . . . . . | $$ | . . . O X X O . O . . . . O . X . . . | $$ | . . X X X . 1 O . , . . . . . , X . . | $$ | . . . . . X O a . . . . . . . O X . . | $$ | . . . . O O O . . . . . . . . . . . . | $$ | . . O . O X X X . . . . . . O O O . . | $$ | . . . O X X . . . . . . . . . X X . . | $$ | . . . X . O . . . . . . . . . . . . . | $$ | . . X , . X . . . , . . . . . X . . . | $$ | . . X O X X O . . O . . O . X . . . . | $$ | . . O . X O O . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Click Here To Show Diagram Code: [go]$$B Moves 97 to 97 $$ --------------------------------------- $$ | . . . . . . . . . . . O X X . . . . . | $$ | . . . . . . . . . . . . O X . X . . . | $$ | . O . . O O . . . . . O . O X . . . . | $$ | . X O O . X O O . , . . . O . X . . . | $$ | X . X X 2 X X X O . O . . O . . . . . | $$ | . X . . O O O O X O . . . . . X . . . | $$ | . . . X 1 X X X X . . . . . O X . . . | $$ | . . . X O O O O 3 . . . . . . . . . . | $$ | . . . O X X O 4 O 5 . . . O . X . . . | $$ | . . X X X . 1 O . , . . . . . , X . . | $$ | . . . . . X O a . . . . . . . O X . . | $$ | . . . . O O O . . . . . . . . . . . . | $$ | . . O . O X X X . . . . . . O O O . . | $$ | . . . O X X . . . . . . . . . X X . . | $$ | . . . X . O . . . . . . . . . . . . . | $$ | . . X , . X . . . , . . . . . X . . . | $$ | . . X O X X O . . O . . O . X . . . . | $$ | . . O . X O O . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Of course White won't play this way but that shows Black's original move can't be urgent.

Posted: **Wed Aug 30, 2023 4:38 pm**

If I understand correctly then you are saying that KataGo wants to play a? That is not the case for my setup, here it wants to play b.

At least black will answer a but if black tries to play a ko it feels like a really slow way to start a ko. This and other forcing moves have a similar score here and next black move is always b.

Click Here To Show Diagram Code: [go]$$B $$ --------------------------------------- $$ | . . . . . . . . . . . O X X . . . . . | $$ | . . . . . . . . . . . . O X . X . . . | $$ | . . . . O O . . . . . O . O X . . . . | $$ | . . O O . X O O . , . . . O . X . . . | $$ | . O X X . X X X O . O . . O . . . . . | $$ | . X . . . . . c X O . . . . . X . . . | $$ | . . . X . . . . X . . . . . O X . . . | $$ | . . . X O O O O . . . . . . . . . . . | $$ | . . . O X X O X . . . . . O . X . . . | $$ | . . X X X O a O . , . . . . . , X . . | $$ | . . . . . X O . . . . . . . . O X . . | $$ | . . . . O O O . . . . . . . . . . . . | $$ | . . O . O X X X . . . . . . O O O . . | $$ | . . . O X X . . . . . . . . . X X . . | $$ | . . . X . O . . . . . . . . . . . . . | $$ | . . X , . X . . . , . . . . . X . . . | $$ | . . X O X X O . . O . . O . X . . . . | $$ | . . O . X O O . . . . b . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Alternatively, maybe you meant that if black plays something else and white cuts at c then black can drive the cutting stone and give up the four stones, then he can finally play a? My KataGo will instead do what I half expected and let white have the two stones if he still wants them but does play a first for good measures. For example the diagram,

is btw only one of many good moves.

Click Here To Show Diagram Code: [go]$$B For example $$ --------------------------------------- $$ | . . . . . . . . . . . O X X . . . . . | $$ | . . . . . . . . . . . . O X . X . . . | $$ | . . . . O O . . . . . O . O X . . . . | $$ | . . O O . X O O . , . . . O . X . . . | $$ | . O X X . X X X O . O . . O . . . . . | $$ | . X . . . . . 4 X O . . . . . X . . . | $$ | . . . X . . . . X . . . . . O X . . . | $$ | . . . X O O O O . . . . . . . . . . . | $$ | . . . O X X O X 6 . . . . O . X . . . | $$ | . . X X X O 5 O . , . . . . 7 , X . . | $$ | . . . . . X O . . . . . . . . O X . . | $$ | . . . . O O O . . . . . . . . . . . . | $$ | . . O 2 O X X X . . . . . . O O O . . | $$ | . 3 1 O X X . . . . . . . . . X X . . | $$ | . . . X . O . . . . . . . . . . . . . | $$ | . . X , . X . . . , . . . . . X . . . | $$ | . . X O X X O . . O . . O . X . . . . | $$ | . . O . X O O . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

If we assume Takagawa's negative move was intentional then the other question besides style considerations is if this really is a good way to win in the position. Maybe playing b is easiest?

Posted: **Wed Aug 30, 2023 11:24 pm**

Knotwilg wrote: A key point in the game is the peep at , in this diagram . Takagawa responded with the intuitive connection

KataGo says that in this case, the proverbial moron should not connect against the peep. Black can instead play :b2:here. If White cuts, Black makes life in profit in the corner and the three stones are out. If White instead connects at then Black has made a favorable exchange before connecting at

I think this may be another move where the strategic direction is more important than a few points. If Black lets White cut, then Black can make some profit in the corner but has less control in the centre with the three stones cut off. Having three stones cut off may not pose any immediate threat for Black, but it opens up possibilities for White to try to steer the direction of the game in a way they prefer and/or exploit the situation later on.

Posted: **Thu Aug 31, 2023 1:23 am**

kvasir wrote:If I understand correctly then you are saying that KataGo wants to play a? That is not the case for my setup, here it wants to play b.

I'll check again but indeed after some time A was the blue move. Around your B were many green moves too.

kvasir wrote: Alternatively, maybe you meant that if black plays something else and white cuts at c then black can drive the cutting stone and give up the four stones, then he can finally play a?

Not what I meant - but it all boils down to the same thing. Playing the ko at some point gives more leverage than Takagawa's dull double empty triangle.

kvasir wrote: My KataGo will instead do what I half expected and let white have the two stones if he still wants them but does play a first for good measures. For example the diagram, is btw only one of many good moves.

$$B For example
$$ ---------------------------------------
$$ | . . . . . . . . . . . O X X . . . . . |
$$ | . . . . . . . . . . . . O X . X . . . |
$$ | . . . . O O . . . . . O . O X . . . . |
$$ | . . O O . X O O . , . . . O . X . . . |
$$ | . O X X . X X X O . O . . O . . . . . |
$$ | . X . . . . . 4 X O . . . . . X . . . |
$$ | . . . X . . . . X . . . . . O X . . . |
$$ | . . . X O O O O . . . . . . . . . . . |
$$ | . . . O X X O X 6 . . . . O . X . . . |
$$ | . . X X X O 5 O . , . . . . 7 , X . . |
$$ | . . . . . X O . . . . . . . . O X . . |
$$ | . . . . O O O . . . . . . . . . . . . |
$$ | . . O 2 O X X X . . . . . . O O O . . |
$$ | . 3 1 O X X . . . . . . . . . X X . . |
$$ | . . . X . O . . . . . . . . . . . . . |
$$ | . . X , . X . . . , . . . . . X . . . |
$$ | . . X O X X O . . O . . O . X . . . . |
$$ | . . O . X O O . . . . b . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
Click Here To Show Diagram Code
[go]$$B For example $$ --------------------------------------- $$ | . . . . . . . . . . . O X X . . . . . | $$ | . . . . . . . . . . . . O X . X . . . | $$ | . . . . O O . . . . . O . O X . . . . | $$ | . . O O . X O O . , . . . O . X . . . | $$ | . O X X . X X X O . O . . O . . . . . | $$ | . X . . . . . 4 X O . . . . . X . . . | $$ | . . . X . . . . X . . . . . O X . . . | $$ | . . . X O O O O . . . . . . . . . . . | $$ | . . . O X X O X 6 . . . . O . X . . . | $$ | . . X X X O 5 O . , . . . . 7 , X . . | $$ | . . . . . X O . . . . . . . . O X . . | $$ | . . . . O O O . . . . . . . . . . . . | $$ | . . O 2 O X X X . . . . . . O O O . . | $$ | . 3 1 O X X . . . . . . . . . X X . . | $$ | . . . X . O . . . . . . . . . . . . . | $$ | . . X , . X . . . , . . . . . X . . . | $$ | . . X O X X O . . O . . O . X . . . . | $$ | . . O . X O O . . . . b . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]
If we assume Takagawa's negative move was intentional then the other question besides style considerations is if this really is a good way to win in the position. Maybe playing b is easiest?

Any of

+

or

in this diagram or moves like b which harass the two space jump, are sharp ways to maintain the lead. Of those,

and

take White's growing center into account. With my own playing style, which is not so good at reducing moyos, I might pick

naturally, or

first if I noticed it.

Posted: **Thu Aug 31, 2023 11:55 am**

BTW white can cut just fine.

Click Here To Show Diagram Code: [go]$$W Cutting in the random position (to make it white's move) $$ --------------------------------------- $$ | . . . . . . . . . . . O X X . . . . . | $$ | . . . . . . . . . . . . O X . X . . . | $$ | . . . . O O . . . . . O . O X . . . . | $$ | . . O O . X O O . , . . . O . X . . . | $$ | . O X X . X X X O . O . . O . . . . . | $$ | . X . . 3 . . 1 X O . . . . . X . . . | $$ | . . . X . . . 2 X . . . . . O X . . . | $$ | . . . X O O O O . . . . . . . . . . . | $$ | . . . O X X O . O . . . . O . X . . . | $$ | . . X X X . X O . , . . . . . , X . . | $$ | . . . . . X O . . . . . . . . O X . . | $$ | . . . . O O O . . . . . . . . . . . . | $$ | . . O O O X X X . . . . . . O O O . . | $$ | . X X O X X . . . . . . . . . X X . . | $$ | . . . X . O . . . . . . . . . . . . . | $$ | . . X , . X . . . , . . . . . X . . . | $$ | . . X O X X O . . O . . O . X . . . . | $$ | . . O . X O O . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Playing the endgame in the corner has an effect on the cut.

Click Here To Show Diagram Code: [go]$$W Again making it white's move someway. $$ --------------------------------------- $$ | . . . . . . . . . . . O X X . . . . . | $$ | . . 3 . . . . . . . . . O X . X . . . | $$ | . O 2 . O O . . . . . O . O X . . . . | $$ | . X O O . X O O . , . . . O . X . . . | $$ | X . X X . X X X O . O . . O . . . . . | $$ | . X . . 5 . 6 1 X O . . . . . X . . . | $$ | . . . X . . . 4 X . . . . . O X . . . | $$ | . . . X O O O O . . . . . . . . . . . | $$ | . . . O X X O . O . . . . O . X . X . | $$ | . . X X X . X O . , . . . . . , X . O | $$ | . . . . . X O . . . . . . . . O X . . | $$ | . . . . O O O . . . . . . . . . . . . | $$ | . . O O O X X X . . . . . . O O O O . | $$ | . X X O X X . . . . . . . . . X X . . | $$ | . . . X . O . . . . . . . . . . . X . | $$ | . . X , . X . . . , . . . . . X . . . | $$ | . . X O X X O . . O . . O . X . . . . | $$ | . . O . X O O . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Endgame is so confusing without KataGo second guessing everything, trying to follow how KataGo plays endgame risks losing the marbles. I wonder if it is easier to understand if one wouldn't use same engine for black and white, it is maddening how black and white agree on everything when analyzing.

Posted: **Sat Sep 02, 2023 4:09 am**

The key moves in this game are 31 to 39 where Takagawa is being reduced from both sides. This soft response to White's invasion and reduction is reversing the lead, from +2.5 due to the small komi to -3.5.
From 41 to 45 Black creates a weak group in the lower left

The upper left joseki then seems to turn out rather well for Black so that at 65 he could turn to the lower side again.

69: Instead Takagawa tries his usual tactic of creating a ko, at the upper side this time, to create an advantage elsewhere or attack White's center stones on a large scale.

83: Black does separate the center stones but the ko is still active and his upper side is weak

113-115: allows WHite to execute a squeeze, creating strength to kill the upper side or to capture the central cutting stones. Black saves them but then loses the top side depending on another ko fight. White doesn't even have to win it in order to win the game, so Takagawa resigns, seeing that White is in total control.

Posted: **Sat Sep 02, 2023 4:16 am**

Click Here To Show Diagram Code: [go]$$W Moves 32 to 33 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . O O . O O O . | $$ | . . . O . . . . . , . . . . X X X O . | $$ | . . . . . . . . . . . . . . . . X X . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . O . . . . . , . O 6 . . , . . . | $$ | . . . . . . . . . . . . X . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X X X . | $$ | . . . O . X . . . X . . . 4 X O O X . | $$ | . . . . . . . . . . . . . 2 1 . . O . | $$ | . . . . . . . . . . . . . . 3 . 5 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

The double hane at

is intuitive and easy. It allows to take sente and enlarge the center at

Obviously KataGo is just a little keener on taking the 3-3 in the upper left, but let's put that aside
This diagram is the kind of straightforward Go an amateur would expect to learn from a pro.

Why Takagawa plays the softer game sequence may be because he expects to benefit from the aji later, perhaps in a ko.

Posted: **Sat Sep 02, 2023 4:22 am**

Click Here To Show Diagram Code: [go]$$B Position at move 65 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . O O O X X . . . . . . . . . . . . . | $$ | . . X X O O X . . X . a O O . O O O . | $$ | . . X O . . . . . , . . . . X X X O . | $$ | . . . O . O c . . . . . . . . . X X . | $$ | . . . O . . . . . . . . O . . X O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . 0 . . . . X . . . | $$ | . . . O . . . X . O 9 O O . . , . . . | $$ | . . . . . . . . . . b X X . X . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . . . . . . . . . . . | $$ | . . X O . X . . . . . . . . . . . . . | $$ | . . X . . 3 . . . . . . . . . X X X . | $$ | . . O O O X 2 . . X . . . X X O O X . | $$ | . . . . . O 1 5 7 . . X X O O . . O . | $$ | . . . . . . 4 6 . . . . O . . . 8 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Instead of A, Black could play at the bottom first. When the exit towards the left is blocked, White might take care of his corner at

. Then Black solidifies the center with

and next B.

This keeps the game very close. Black can play this way, recovering from his lukewarm opening, because White allowed him to settle at the top too easily. Later, Black can attach at C to move out, should he not be able to live locally.

This way of playing would again be in line with the alleged style of "keeping things simple and count on a superior endgame" while Takagawa again seeks complexity with A and for the third game in a row shows a preference for ko as a means to win the game by making major exchanges.

Posted: **Sat Sep 02, 2023 3:38 pm**

Comments inside the game. Move 91 is quite particular.

Posted: **Sat Sep 02, 2023 3:49 pm**

Click Here To Show Diagram Code: [go]$$B Moves 35 to 35 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . O . . . . . . . . O O . . . . | $$ | . O O O . . O . X , . . O X . X . . . | $$ | . X X X . X . . 4 . . . . X . X . . . | $$ | . . . . . . . X . . . 2 . . . O X . . | $$ | . . . . . . . . . . . . . . . 3 . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . O . . . | $$ | . . X , . . . . . , . . W . O , . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . X . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . O . . . , . . . . . X 1 . . | $$ | . . . . . . . . . O . . X . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

A first key moment is when Black solidifies his territory with

after White has erased the left side and ran out at the marked move. This allows White to take the initiative with

and cut with

Click Here To Show Diagram Code: [go]$$B Moves 35 to 35 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . O . . . . . . . . O O . . . . | $$ | . O O O . . O . X , . . O X . X . . . | $$ | . X X X . X . . . . . . . X . X . 9 . | $$ | . . . . . . . X . . . . . . 6 O X . . | $$ | . . . . . . . . . . . . . a . 5 4 7 . | $$ | . . . . . . . . . . . . . . . . 8 0 . | $$ | . . . . . . . . . . . . . 1 . O . . . | $$ | . . X , . . . . . , . . O 2 O , . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . 3 . X . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . O b . . , . . . . . X . . . | $$ | . . . . . . . . . O . . X . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

It would have been more active to keep up the pressure here. If White now would play the keima from the previous diagram, his group will come under pressure. White can launch a skirmish in the upper right, which strengthens both weak groups. Black can further settle locally at A. KataGo would be audacious and play B.

Posted: **Sat Sep 02, 2023 4:08 pm**

Click Here To Show Diagram Code: [go]$$B Moves 79 to 79 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . O . . | $$ | . . . . O O . O . . . . . O O . . . . | $$ | . O O O . X O X X , . . O X . X . . . | $$ | . X X X . X . X O . . X O X . X . . . | $$ | . . . . . . . X . . . O O . . O X . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . O . O . | $$ | . . X , . X . . . , . . O . O , . X . | $$ | . . . . . . . 1 . . . . . . . X X X . | $$ | . . X . . . . . . . . . . . X . O O . | $$ | . X O . O . . . . . . . O . X . . . . | $$ | . O . O . . . . . . . . . . O X . . . | $$ | . . O . . . . . . . . . O . O . . . . | $$ | . X O O . O . . . , . . . X . X X . . | $$ | . X X O . . . . . O . . X . . . . . . | $$ | . X . X O . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ ---------------------------------------[go] A second key move is this reduction/expansion. It's on the boundary of moyos indeed but the problem with it is that White's lower left is very strong and there are weaker areas that can use some attantion. [go] $$B Moves 79 to 79 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . O . . | $$ | . . . . O O . O . . . . . O O . . . . | $$ | . O O O . X O X X , . . O X . X . . . | $$ | . X X X . X . X O . . X O X . X . . . | $$ | . . . . . . . X . . . O O . . O X . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . O . O . | $$ | . . X , . X . . . , . . O . O , . X . | $$ | . . . . . . . 5 . . . . . . . X X X . | $$ | . . X . . . . . . . . . . . X . O O . | $$ | . X O . O . . . . . . . O . X . . . . | $$ | . O . O . . . . . . . . . . O X . . . | $$ | . . O . . . . . . . . . O . O . . . . | $$ | . X O O . O . . . , 4 . . X . X X . . | $$ | . X X O . . . . . O 3 . X . . . . . . | $$ | . X . X O . . . . 2 1 . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

If Black can reduce at the bottom in sente first, then his original move is better timed.

Click Here To Show Diagram Code: [go]$$B Moves 79 to 79 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . 4 O . . | $$ | . . . . O O . O . . . . . O O 3 1 2 . | $$ | . O O O . X O X X , . . O X . X . 5 . | $$ | . X X X . X . X O . . X O X . X . . . | $$ | . . . . . . . X . . . O O . . O X . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . O . O . | $$ | . . X , . X . . . , . . O . O , . X . | $$ | . . . . . . . 9 . . . . . . . X X X . | $$ | . . X . . . . . . . . . . . X . O O . | $$ | . X O . O . . . . . . . O . X . . . . | $$ | . O . O . . . . . . . . . . O X . . . | $$ | . . O . . . . . . . . . O . O . . . . | $$ | . X O O . O . . . , . . . X . X X . . | $$ | . X X O . . . . . O . 8 X . . . . . . | $$ | . X . X O . . . . . . 6 7 . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

In fact both Black and White could also respond on top of the respective keimas to make the situation a little more complicated but if we stick with the more mundane blocks, this i

In fact, KataGo seems to think of these reducing moves as miai and prefers making the upper right corner alive with points.

Posted: **Mon Sep 04, 2023 9:52 am**

A two point win by Takagawa. Two kofights determine the game, the second making for a large swap that divides the board into two. Eventually the lead drops from about 8 to only 2 points.

Life In 19x19

A study of Takagawa

Re: A study of Takagawa

Re: A study of Takagawa

Re: A study of Takagawa

Re: A study of Takagawa

Re: A study of Takagawa

Re: A study of Takagawa

Re: A study of Takagawa

Re: A study of Takagawa

Re: A study of Takagawa

Re: A study of Takagawa

Re: A study of Takagawa

Re: A study of Takagawa

Re: A study of Takagawa

Re: A study of Takagawa

Re: A study of Takagawa