Opening problems for AI: Problem 34

Bill Spight · Post by **Bill Spight** » Sat Jul 18, 2020 3:50 am

Black to play.

Click Here To Show Diagram Code: [go]$$Bcm13 Black to play. $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . X . . . . | $$ | . . . , O . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . . . . . . . . . . . . . | $$ | . . . X . X O . . . . . . . . . O . . | $$ | . . X , . O . . . , . . . . . , . . . | $$ | . . . . O . . . O . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

This looks like an Edo period game, and it is. Black's textbook play loses 23½% to par, according to Elf, which pretty well puts it in the blunder category. Assuming komi, as always.

Enjoy!

Bill Spight · Post by **Bill Spight** » Tue Jul 21, 2020 5:38 am

No bites for this one, either. Well, there are a few attractive places to play. And the joseki in the bottom left is unfamiliar.

Click Here To Show Diagram Code: [go]$$Bcm13 Black to play. $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . X . . . . | $$ | . . . , O . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . . . . . . . . . . . . . | $$ | . . . X . X O . . . . . . . . . O . . | $$ | . . X , . O . . . , . . . . . , . . . | $$ | . . . . O . . . O . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

That's because this joseki is obsolete.

Click Here To Show Diagram Code: [go]$$Bc Obsolete $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ | . . . 3 . . . . . . . $$ | . . 1 , . 4 . . . , . $$ | . . . . 2 . . . . . . $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ ----------------------[/go]

is not played much, anymore. And the reason for that, says Kogo's Joseki Dictionary, is that "Black gets a favorably thick shape." To wit:

Click Here To Show Diagram Code: [go]$$Bc Thick shape $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ | . . . . . 7 9 . . . . $$ | . . . 3 . 5 6 . . . . $$ | . . 1 , . 4 . . . , . $$ | . . . . 2 . . . 8 . . $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ ----------------------[/go]

It does seem, however, that

is making a comeback in this century. When there is some strength to back it up.

Bill Spight · Post by **Bill Spight** » Tue Jul 21, 2020 7:10 am

The position after

comes from the game, GoGoD 1787-06-26a, between Honinbo Retsugen, 6 dan (W) and Yasui Senchi Senkaku, 5 dan.

Click Here To Show Diagram Code: [go]$$Wcm8 Moves 8 to 12, Comedy of errors $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . X . . . . | $$ | . . . , O . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 7 . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . 4 6 . . . . . . . . . . . . | $$ | . . . X . 2 3 . . . . . . . . . O . . | $$ | . . X , . 1 . . . , . . . . . , . . . | $$ | . . . . O . . . 5 . . . . . . a . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Elf, assuming komi, OC, says that

loses 14% to par, and then

returns the favor, losing 14½% to par.

and

are fine, but then

loses 16½%. Finally,

loses a whopping 23½% to par!

I confess that, seeing this joseki any number of times in old games, I had my doubts about

, but

looked good to me. And apparently

fell out of favor because the result through

looked too good for Black to top players in the 19th century, as well. Elf, however, reckons that the sequence,

-

, loses 21%.

is a borderline error, losing 5½%. It is thin, OC, but it does counter Black's thickness. Elf prefers to enclose the bottom right corner.

Click Here To Show Diagram Code: [go]$$Wcm14 Variation for :w14: $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 3 . . . . . . . . . . . X . . . . | $$ | . . 2 , O . . 5 . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 4 . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X X . . . . . . 8 . 6 . . . | $$ | . . . X . X O . . . . . . . . 7 O . . | $$ | . . X , . O . . . , . . . . . , . . . | $$ | . . . . O . . . O . . . . . . 1 . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

After

, Black's play is interesting.

could also be at 16, OC, but we may consider

as a probe. After White replies at

,

plays a long extension from his thickness. Takagawa explains this kind of tenuki by saying that Black has prevented an ideal play for White (the usual enclosure) with sente, and can be satisfied with that.

is the Go Seigen/AlphaGo shoulder hit. The light jump,

, is a shallow reduction of White's bottom side framework.

Top choice: Invade the bottom right corner

Click Here To Show Diagram Code: [go]$$Bcm13 3-3 invasion $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . X . . . . | $$ | . . . , O . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . b . . | $$ | . . . . . X . . . . . . . . 9 8 a . . | $$ | . . . X . X O . . . . . . . 4 7 O . . | $$ | . . X , . O . . . , . . . . 2 3 . . . | $$ | . . . . O . . . O . . . . 6 5 . 1 . . | $$ | . . . . . . . . . . . . . . 0 . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

The 3-3 invasion against the 5-3 is obviously a good play, now that the bots like it.

stands to block Black out of the bottom side.

cuts high. If Black cuts at a he suffers the atari at b.

Click Here To Show Diagram Code: [go]$$Bcm23 Mainline, continued $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . X . . . . | $$ | . . . , O . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . 0 . . . | $$ | . . . . . . . . . . . . . . . 8 9 . . | $$ | . . . . . . . . . . . . . . . 6 7 . . | $$ | . . . . . . . . . . . . . . . 4 5 . . | $$ | . . . . . X . . . . . . . . X O 3 . . | $$ | . . . X . X O . . . . . . . O X O . . | $$ | . . X , . O . . . , . . . 2 O X . . . | $$ | . . . . O . . . O . . . . O X 1 X . . | $$ | . . . . . . . . . . . . . . O . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

connects, and

eliminates a cutting point.

is atari. White builds a strong wall while Black makes territory on the 3d line. A few years ago I would have considered this lengthy exchange to be good for White. Each push by Black gains about 2 pts. of territory, while I figured that each extension on the 4th line gains on average more than 3 pts. In addition there is the proverb about not pushing the cart from behind. Live and learn.

Click Here To Show Diagram Code: [go]$$Bcm33 Mainline, continued again $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . X . . . . | $$ | . . 4 , O . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . 2 . . . | $$ | . . . , . . . . . , . . . . . O 1 . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . X 3 . . . . . . . X O X . . | $$ | . . . X . X O . . . . . . . O X O . . | $$ | . . X , . O . . . , . . . O O X . . . | $$ | . . . . O . . . O . . . . O X X X . . | $$ | . . . . . . . . . . . . . . O . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

pushes once more, and now the turn is good for

.

encloses the top left corner.

Again, long variations should be taken with a grain of salt.

OC, invading the bottom right corner is a good play, but what is wrong with

? I confess I don't know. And that's really why I chose this problem. Usually the center turn shape with three stones is good, and this series has shown examples where it is good, whether the result of a turn or of a solid connection. This is an important exception to the rule. I can see how the 3-3 invasion might be preferable, but the difference of more than 20% is quite a shock! Food for thought.

Knotwilg · Post by **Knotwilg** » Tue Jul 21, 2020 8:50 am

I can't keep up

Opening gospel says: upper left corner is biggest, unless there's an urgent move on the lower left.

Click Here To Show Diagram Code: [go]$$Bcm13 Black to play. $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . 6 . . . . . . . . . . . . . . . . . | $$ | . 3 2 4 . . . . . . . . . . X . . . . | $$ | . 7 1 , O . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 5 . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . . . . . . . . . . . . . | $$ | . . . X . X O . . . . . . . . . O . . | $$ | . . X , 0 O . . . , . . . . . , . . . | $$ | . . . 9 O . . . O . . . . . . 8 . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

My first 10 moves.
The

-

exchange might be a case of sente but if Black would play it before the upper left, then White can safely ignore, I think.

Gomoto · Post by **Gomoto** » Tue Jul 21, 2020 9:44 am

Boring ...

Your series is not boring at all and I enjoy starting Fat Kata from time to time and comparing her views to my braincells output.

Gomoto · Post by **Gomoto** » Tue Jul 21, 2020 9:54 am

But after some time ...

Such a pretty shape

Bill Spight · Post by **Bill Spight** » Tue Jul 21, 2020 10:34 am

Gomoto wrote:But after some time ...
bill34.JPG

bill34.2.JPG
Such a pretty shape

Thanks for checking with KataGo.

I have run across that variation in other games, BTW.

dhu163 · Post by **dhu163** » Mon Dec 26, 2022 6:58 am

Life In 19x19

Opening problems for AI: Problem 34

Opening problems for AI: Problem 34

Re: Opening problems for AI: Problem 34

Re: Opening problems for AI: Problem 34

Re: Opening problems for AI: Problem 34

Re: Opening problems for AI: Problem 34

Re: Opening problems for AI: Problem 34

Re: Opening problems for AI: Problem 34

Re: Opening problems for AI: Problem 34