This has been making me lose sleep the past few days...

komondor · Post by **komondor** » Thu Feb 19, 2015 11:53 pm

Greetings! I am a new member and I have been wondering about these two 9x9 openings. Who has the advantage from these two positions, black or white (with 5.5 komi)? I have tried playing against myself and various programs, and my instincts say that on the left white has better positioning, and on the right, black has better positioning, but i still cannot decide for sure. I would greatly appreciate any and all discussion! I apologize if this has been answered before - I am not how to search it.

EdLee · Post by **EdLee** » Thu Feb 19, 2015 11:55 pm

Hi komondor,

Welcome.

Continue to play. Play. Play. And play. :mrgreen:

tentano · Post by **tentano** » Fri Feb 20, 2015 3:01 am

Both positions seem bad for white.

Black is connected, white is split in two. I'm not even confident I could keep both white groups alive in either position.

Elom · Post by **Elom** » Fri Feb 20, 2015 3:53 am

tentano wrote:Both positions seem bad for white.

Black is connected, white is split in two. I'm not even confident I could keep both white groups alive in either position.

Doesn't white have sente? With a 5.5 komi white doesn't seem too bad (unless I'm missing something)

tentano · Post by **tentano** » Fri Feb 20, 2015 4:14 am

It seems bad enough to me that I wouldn't want to be in that position. I would never cooperate with a black side to get into either of those positions.

I don't even recall ever seeing either position, so it needs to be drastically bad for one side, at least.

skydyr · Post by **skydyr** » Fri Feb 20, 2015 7:59 am

tentano wrote:Both positions seem bad for white.

Black is connected, white is split in two. I'm not even confident I could keep both white groups alive in either position.

White has the connection tesuji at the 2-5 point to connect in the second diagram. IMO, this makes it a lot better for white than the first.

With sente to start cutting, also, I think white's doing okay in both. If white loses with perfect play, it doesn't seem like it would be by a lot.

illluck · Post by **illluck** » Fri Feb 20, 2015 8:16 am

Huh, seems like we have completely different assessments. I prefer white in the first situation and black in the second.

Unusedname · Post by **Unusedname** » Fri Feb 20, 2015 12:56 pm

Haha I like black better in the first but white in the second.

Also i don't think white can connect underneath because of black peeping underneath either of the two white groups.

Elom · Post by **Elom** » Sat Feb 21, 2015 12:23 am

Unusedname wrote:Haha I like black better in the first but white in the second.

Also i don't think white can connect underneath because of black peeping underneath either of the two white groups.

I prefer White in the first diagram, and Black in the second :blackeye:

Kanin · Post by **Kanin** » Sat Feb 21, 2015 4:37 am

komondor wrote:Greetings! I am a new member and I have been wondering about these two 9x9 openings. Who has the advantage from these two positions, black or white (with 5.5 komi)? I have tried playing against myself and various programs, and my instincts say that on the left white has better positioning, and on the right, black has better positioning, but i still cannot decide for sure. I would greatly appreciate any and all discussion! I apologize if this has been answered before - I am not how to search it.

This will be quite unscientific, but... My instinct tells me that white's sente in the symmetrical position on the bottom is worth less than in the mirror-position on the top because there is no good symmetrical point for white to play with her next move. And she will have to take an asymmetrical gote somewhere. But in the top position white could in theory keep sente throughout the entire endgame. Just an intuitive thought.

komondor · Post by **komondor** » Sat Feb 21, 2015 11:32 am

skydyr wrote:White has the connection tesuji at the 2-5 point to connect in the second diagram. IMO, this makes it a lot better for white than the first.

With sente to start cutting, also, I think white's doing okay in both. If white loses with perfect play, it doesn't seem like it would be by a lot.

After some more experimenting, I have concluded that this is the right answer, that white wins in both cases. In the first, white wins by simply maintaining sente throughout most of the game, and in the second white wins by playing the next move at B-2. If anyone can find a novel way for black to win, I would love to see it.

Bill Spight · Post by **Bill Spight** » Sat Feb 21, 2015 12:21 pm

komondor wrote:
skydyr wrote:White has the connection tesuji at the 2-5 point to connect in the second diagram. IMO, this makes it a lot better for white than the first.

With sente to start cutting, also, I think white's doing okay in both. If white loses with perfect play, it doesn't seem like it would be by a lot.

After some more experimenting, I have concluded that this is the right answer, that white wins in both cases. In the first, white wins by simply maintaining sente throughout most of the game, and in the second white wins by playing the next move at B-2. If anyone can find a novel way for black to win, I would love to see it.

The 9x9 is not my forte, so I am not sure, but I suspect that Black cannot overcome the komi in either case.

However, White cannot simply win in the first case by maintaining sente. Whichever group White plays from with :w10:

, Black should attack the other one with :b11:

.

komondor · Post by **komondor** » Sat Feb 21, 2015 2:31 pm

Bill Spight wrote:However, White cannot simply win in the first case by maintaining sente. Whichever group White plays from with , Black should attack the other one with .

That is true, I overlooked the fact that black should attack the other group and white would lose sente. But even then, black would have to kill one of the groups to win, and I do not think that is possible if white plays ideally.

Alcadeias · Post by **Alcadeias** » Sat Feb 21, 2015 3:34 pm

Click Here To Show Diagram Code: [go]$$B $$ +-------------------+ $$ | . . . . . . . . . | $$ | . . . . . . . . . | $$ | . . X . O . O . . | $$ | . . . . . . . . . | $$ | . . X . X . X . . | $$ | T T T T T T . . . | $$ | C C W C W T X . . | $$ | C C C C C T . . . | $$ | C C C C C T . . . | $$ +-------------------+[/go]

In average at the bottom, White should expect to get all of the circled points and half of the triangle points.
So White can expect to have 15 + 9/2 = 19.5 points at the bottom, and the same amount of points at the top since the position is symmetric, which makes for a total of 39 points.
And therefore we get this approximate evaluation of the position: (40.5 - 39) * 2 = +3
With a komi of 5.5 White should have the advantage.
But I'm just a patzer. This simplistic calculation is probably not so helpful.

Life In 19x19

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