Life In 19x19

Posted: **Sun Dec 08, 2019 3:34 pm**

Discussion of the Elf commentary

After

Elf estimates a winrate of 91½% for one player. Which player is it?

Black.

But White won by resignation.

Click Here To Show Diagram Code: [go]$$Bcm31 Black is ahead $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . O . O . . | $$ | . . . , . . . . . , . . . . . , X X . | $$ | . . . . . . . . . . . . . . . O X O . | $$ | . . . . . . . . . . . . . . . O O X . | $$ | . . . . . . . . . . . . . . . O X X . | $$ | . . . . . . . . . . . . . . O O X . . | $$ | . . . . . . . . . . . . . X O X . . . | $$ | . . . , . . . . . , . . . O X , . . . | $$ | . . . . . . . . . . . . . O X . . . . | $$ | . . . . . . . . . . . . O X a . . . . | $$ | . . . . . . . . . . . . 1 . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . X , . . . . . , . . . . . , . . . | $$ | . . . . O . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

This game is GoGoD 1967-05-23a, the third game of the 22d Honinbo final between Sakata Eio (W) and Rin Kaiho (Lin Haifeng).

First, let me note that this game could be in the Beat Elf! thread ( viewtopic.php?f=15&t=16641 ). Elf's first choice for

is at a, but then it awards Lin's two step hane an 8% higher winrate, even though Lin's play was almost entirely off of Elf's radar, with only one rollout.

Elf's recommended continuation

Click Here To Show Diagram Code: [go]$$Wcm32 Elf's continuation $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . O . O . . | $$ | . . . , . . . . . , . . . . 9 8 X X . | $$ | . . . . . . . . . . . . . . . O X O . | $$ | . . . . . . . . . . . . . . . O O X . | $$ | . . . . . . . . . . . . . . . O X X . | $$ | . . . . . . . . . . . . . . O O X . . | $$ | . . . . . . . . . . . . . X O X . . . | $$ | . . . , . . . . . , . . . O X , . . . | $$ | . . . . . . . . . . . . . O X . . . . | $$ | . . . . . . . . . . . 1 O X 2 . . . . | $$ | . . . . . . . . . . . 3 X . . . . . . | $$ | . . . . . . . . . . 5 4 6 . . . . . . | $$ | . . . . . . . . . . 7 . . . . . X . . | $$ | . . X , . . . . . , . . . . . , . . . | $$ | . . . . O . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

White extends, Black connects, then White turns and Black plays another two step hane. The descent,

, is big. After

the rollouts drop below 1500, so Elf's variation ends. I anticipate a reduction of White's huge sphere of influence.

Earlier in the game

The record of this game made a big impression on me as a kyu player. I was familiar with the joseki in the top right corner, but not with it carried out to this extent. I remember thinking, My God, do I have to learn all of this?

There are two standout errors in the play, according to Elf. The first is

.

Click Here To Show Diagram Code: [go]$$Bcm23 :b23: loses 14% to par $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . O . O . . | $$ | . . . , . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . O X O . | $$ | . . . . . . . . . . . . . . . O O X . | $$ | . . . . . . . . . . . . . . . O X X . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . 1 O X . . . | $$ | . . . , . . . . . , . . . . X , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . X , . . . . . , . . . . . , . . . | $$ | . . . . O . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

This move is a mistake?

Why, doesn't it force White to make an empty triangle? Yes, it leaves a few cutting points, but Black can protect.

Elf's recommended variation

Click Here To Show Diagram Code: [go]$$Bcm23 Elf's mainline variation $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . O . O . . | $$ | . . . , . . . . . , . . . . . , X 1 . | $$ | . . . . . . . . . . . . . . . O X W . | $$ | . . . . . . . . . . . . . . . O O X . | $$ | . . . . . . . . . . . . . . . O X X . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . 4 O X 3 . . | $$ | . . . , . . . . . , . . . . X 2 . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . X , . . . . . , . . . . . , . . . | $$ | . . . . O . 5 . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Elf recommends capturing the

stone in the top right corner, and, after

-

, the one space pincer,

, which also serves as a ladder breaker.

Sakata's blunder

Click Here To Show Diagram Code: [go]$$Wcm24 :w24: is a blunder, losing 28½% to par $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . O . O . . | $$ | . . . , . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . O X O . | $$ | . . . . . . . . . . . . . . . O O X . | $$ | . . . . . . . . . . . . . . . O X X . | $$ | . . . . . . . . . . . . . . 1 O X . . | $$ | . . . . . . . . . . . . . X O X . . . | $$ | . . . , . . . . . , . . . . X , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . X , . . . . . , . . . . . , . . . | $$ | . . . . O . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Surely you jest.

OK, what does Elf recommend?

Click Here To Show Diagram Code: [go]$$Wcm24 Elf's mainline variation $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 4 . O . . . . . . . . . O . O . . | $$ | . . . , . . . . . , . . . . . , X 1 . | $$ | . . . . . . . . . . . . . . . O X O . | $$ | . . . . . . . . . . . . . . . O O X . | $$ | . . . . . . . . . . . . . . . O X X . | $$ | . . . . . . . . . . . . . . 2 O X . . | $$ | . . . . . . . . . . . . . X O X . . . | $$ | . . . , . . . . . , . . . . X , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . X , . . . . . , 3 . . . . , . . . | $$ | . . . . O . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Isn't

worth 30 points, versus that measly corner? OC,

checks Black's expansion on the bottom side. Then

invades the top left corner.

I don't make the news, folks, I just report it. Explaining all this is above my pay scale. That's twice this game has made a big impression on me.

Posted: **Sun Dec 08, 2019 5:26 pm**

I think one key factor why the ponnuki isn't great for black and white is happy to trade is the fact White didn't yet make the Q10 r11 exchange. White can later peep at that cutting point to get 1 in sente to help with a possible invasion. R10 is obviously a far better place to have a white stone than Q10 given black has one at r11. The s11 peep is another way to use the cut weakness.

Click Here To Show Diagram Code: [go]$$Wc later invasion aji $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . O . . . . . . . . . O . O . . | $$ | . . . , . . . . . , . . . . . , X O . | $$ | . . . . . . . . . . . . . . . O X O . | $$ | . . . . . . . . . . . . . . . O O X . | $$ | . . . . . . . . . . . . . . . O X X . | $$ | . . . . . . . . . . . . . . X O X . . | $$ | . . . . . . . . . . . . . X . X 2 . . | $$ | . . . , . . . . . , . . . . X , 1 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . 3 . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . X , . . . . . , O . . . . , . . . | $$ | . . . . O . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Posted: **Mon Dec 09, 2019 12:07 pm**

Since Elf admits to misevaluating

, because Lin's move was better, I expect that it misevaluated earlier plays as well. It did not prefer

, but it did not, I guess, give it a low enough winrate. I now think that it should have said that it loses 9% to par. Here is it's recommended play, instead.

Click Here To Show Diagram Code: [go]$$Wcm28 Elf's mainline for :w28: $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O . W . 0 . . . . . O . O . . | $$ | . . . , . . . . . , . . . . 3 2 X X . | $$ | . . . . . . . . . . . . . . . O X O . | $$ | . . . . . . . . . . . . . . . O O X . | $$ | . . . . . . . . . . . . . . . O X X . | $$ | . . . . . . . . . . . . . . O O X . . | $$ | . . . . . . . . . . . . 9 X O X 4 . . | $$ | . . . , . . . . . , . . . O X 1 . . . | $$ | . . . . . . . . . . . . . 5 X . . . . | $$ | . . . . . . . . . . . . . 7 6 . . . . | $$ | . . . . . . . . . . . . . . 8 . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . X , . . . . . , . . . . . , . . . | $$ | . . . . O . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

=

plays the atari right away.

plays kikashi before connecting. Then, with

in place, Black does not hane at the head of

or

, but simply extends.

is a wedge to reduce the influence of White's wall.

attacks

, making a small base at the same time.

Posted: **Fri Dec 20, 2019 11:56 am**

Rin had beaten Sakata in the 1965 Meijin and kept the title in 1966 and 1967, so Rin's first Honinbo challenge in 1967 was something special.

It fascinated me at the time that Sakata playing White used the sequence in the top right corner in this game and then again in Game 5. The first time he played it, it must have put a lot of pressure on Rin and Sakata won. When Sakata played it again I was stunned, I would love to know what Rin thought. Rin lost Game 5 btw and Sakata kept his Honinbo title.

I suspect that if AI had been around then, Sakata would still have played as he did in Game 5 - he would have valued the psychological pressure more than that AI % win rate.

: Sakata - Rin 1967 Honinbo - Game 3-medium.jpg (190.65 KiB) Viewed 22092 times

The photo shows Game 3 - Sakata on the right, Rin on left. Takagawa is watching, with Murakami Bunsho (Amateur Honinbo) to the left of Takagawa. I spoke to Murakami in 1970 about Sakata, he said he couldn't win an even game but had a chance on 2 stones.

As I said in a previous post - this game is the highlight game in a two volume collection of Sakata's games, the other four games from the 22nd Hononbo also feature.

Never a dull moment.

John

Posted: **Mon Dec 26, 2022 11:50 am**

Surprising. And useful as this is a fairly standard fuseki shape that I've seen (once) even in recent katago self-play.

Life In 19x19

How is your positional judgement? Game 21

Re: How is your positional judgement? Game 21

Re: How is your positional judgement? Game 21

Re: How is your positional judgement? Game 21

Re: How is your positional judgement? Game 21

Re: How is your positional judgement? Game 21