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| This has been making me lose sleep the past few days... http://prod.lifein19x19.com/viewtopic.php?f=10&t=11493 |
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| Author: | komondor [ Thu Feb 19, 2015 11:53 pm ] |
| Post subject: | This has been making me lose sleep the past few days... |
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.  
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| Author: | EdLee [ Thu Feb 19, 2015 11:55 pm ] |
| Post subject: | |
Hi komondor, Welcome.  Continue to play. Play. Play. And play. 
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| Author: | tentano [ Fri Feb 20, 2015 3:01 am ] |
| Post subject: | Re: This has been making me lose sleep the past few days... |
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. |
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| Author: | Elom [ Fri Feb 20, 2015 3:53 am ] |
| Post subject: | Re: This has been making me lose sleep the past few days... |
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) |
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| Author: | tentano [ Fri Feb 20, 2015 4:14 am ] |
| Post subject: | Re: This has been making me lose sleep the past few days... |
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. |
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| Author: | skydyr [ Fri Feb 20, 2015 7:59 am ] |
| Post subject: | Re: This has been making me lose sleep the past few days... |
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. |
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| Author: | illluck [ Fri Feb 20, 2015 8:16 am ] |
| Post subject: | Re: This has been making me lose sleep the past few days... |
Huh, seems like we have completely different assessments. I prefer white in the first situation and black in the second. |
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| Author: | Unusedname [ Fri Feb 20, 2015 12:56 pm ] |
| Post subject: | Re: This has been making me lose sleep the past few days... |
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. |
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| Author: | Elom [ Sat Feb 21, 2015 12:23 am ] |
| Post subject: | Re: This has been making me lose sleep the past few days... |
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 
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| Author: | Kanin [ Sat Feb 21, 2015 4:37 am ] |
| Post subject: | Re: This has been making me lose sleep the past few days... |
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. |
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| Author: | komondor [ Sat Feb 21, 2015 11:32 am ] |
| Post subject: | Re: This has been making me lose sleep the past few days... |
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. |
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| Author: | Bill Spight [ Sat Feb 21, 2015 12:21 pm ] |
| Post subject: | Re: This has been making me lose sleep the past few days... |
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  , Black should attack the other one with  .
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| Author: | komondor [ Sat Feb 21, 2015 2:31 pm ] |
| Post subject: | Re: This has been making me lose sleep the past few days... |
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. |
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| Author: | Alcadeias [ Sat Feb 21, 2015 3:34 pm ] |
| Post subject: | Re: This has been making me lose sleep the past few days... |
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. |
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