In its GoGoD commentaries, after
Elf estimates the winrate for one player as 88½% (73.5k playouts). Elf assumes area scoring with 7½ pts. komi. Which player is it?White has captured 1 Black stone.
Enjoy!
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| How is your positional judgement? Game 23 http://prod.lifein19x19.com/viewtopic.php?f=15&t=17075 |
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| Author: | Bill Spight [ Thu Nov 21, 2019 11:17 am ] |
| Post subject: | How is your positional judgement? Game 23 |
In its GoGoD commentaries, after Elf estimates the winrate for one player as 88½% (73.5k playouts). Elf assumes area scoring with 7½ pts. komi. Which player is it?
White has captured 1 Black stone. Enjoy!
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| Author: | Kirby [ Thu Nov 21, 2019 11:22 am ] |
| Post subject: | Re: How is your positional judgement? Game 23 |
White's gotta be ahead. I'd hate to have that floating black group.. |
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| Author: | jlt [ Thu Nov 21, 2019 11:45 am ] |
| Post subject: | Re: How is your positional judgement? Game 23 |
Black has a bit more solid territory, but is low on the top right, and has a weak group which doesn't cut anything since White can easily link up to the ponnuki with M18, and which doesn't have any influence since it is close to a white ponnuki. So I prefer White |
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| Author: | Knotwilg [ Thu Nov 21, 2019 12:08 pm ] |
| Post subject: | Re: How is your positional judgement? Game 23 |
No LZ The position screams White. Black has an ugly lump of floating stones. There are a few counterindications though: - Black has sente - Black has territory in two places - White has a stone on the second line - other than the area top left, White has no territory yet - White's ponnuki can be atari'd again - and Bill has chosen this position, so it shouldn't be as trivial as it looks BUT, still - white has komi - white's two 3-4 stones are worth an enclosure - and that ugly lump of stones - most of all, White has a good move which isn't one for Black: a connection on the second line, linking White's own floating stones up with territory, while a black move there adds a stone to his floating lump But then again, - if Black jumps out, and White connects on the second line, and Black takes the largest point on the left side, isn't that terrible for WHite? - Black's stones may be expendable, while White's aren't Gee, this one's really hard!!! I must stick to my intuition and say "White is ahead" but I have only 55% confidence in my statement edit: with Cgoban, still no LZ I think I'm about to change my mind and give Black ahead. edit: LZ White CAN cut through: Black has a weakness White can exploit! |
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| Author: | bayu [ Thu Nov 21, 2019 1:18 pm ] |
| Post subject: | Re: How is your positional judgement? Game 23 |
I'd hate such a floating black group. I'd even consider sacrificing it. White's weak group can connect under, so is not as weak as black's group. But if it were so easy, black wouldn't be a pro and Bill probably wouldn't choose this position  Arguments for black: with the descent he can separate white groups for good while threaten to make an eye. The two white corners look lonely, while blacks shimari is uncontested. If black is happy with white connecting its weak group under, black can probably sacrifice its stones. The turn on Q12 looks tasty. So, I take black And I am really curious how black manages to turn the floating black group into profit. There is probably a lesson to be learnt there. |
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| Author: | Uberdude [ Thu Nov 21, 2019 2:32 pm ] |
| Post subject: | Re: How is your positional judgement? Game 23 |
Hard for me to imagine how that weird shape arose, so I'll try a static position evaluation this time. Good thing it's black sente otherwise definitely White. Hot area is top right fighting, but first let's count the rest of the board. I don't really know how to count high shimari (about 10 points?) Or the white 3-4s (6 each?) But as all are decent opening moves let's say about even or a little better for White (because going first in empty corner is better than shimari) and 12 is a bit more than 10. Top right black is about 15 points (q17 sente) which is the same as if White gets territory up to 3rd line E->J which seems plausible (eg if black approach and White kosumi or knight, if pincer then black gets a weak group but White may get less immediate territory there). So minus the fight and black sente White leads by Komi plus 1 capture plus the anount 2 corners are better than a shimari (and j16 thickness probably means d17 can become a chunkier corner than the other). So about 10 points. So the fight. Black should probably jump out around n/o12. Does this force White to connect in gote at M18 or can he resist and break out or at least cut black in sente first? If White crudely boks his way out black seems ok and N12 can be captured in a ladder so that's not a worry, But can 34 crosscut or some better shape? Anyway first as a baseline we can have White simply M18 and then the question is a black stone at o12 and sente worth 10 points? My feeling is not, white can still cut later and if black connects White can just shimari in lower right.
Also isn't there a problem with trying to enclose with corner aji. Maybe black can try to q17 in sente first but it's not really sente as white can probably resist with jump in key area and when if it is that corner aji is still a ko.
So now I say definitely White. |
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| Author: | Knotwilg [ Thu Nov 21, 2019 3:13 pm ] |
| Post subject: | Re: How is your positional judgement? Game 23 |
To Uberdude I missed that last diagram, as you can see in my post. Otherwise me too I had chosen White. Without that aji, I was in doubt, because of the diagrams before. |
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| Author: | hyperpape [ Fri Nov 22, 2019 4:28 pm ] |
| Post subject: | Re: How is your positional judgement? Game 23 |
I favor Black. Both sides have weak groups, which I suspect will both settle imminently. White's upper left corner/side is bigger than Black's upper right, but Black has an enclosure in the lower left which is more valuable than White's lower right. Moreover, I think settling will help to erase the upper left or expand Black's right side. |
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| Author: | jlt [ Sat Nov 23, 2019 1:50 am ] |
| Post subject: | Re: How is your positional judgement? Game 23 |
After reading the comments of Uberdude and Knotwilg, I checked a bit with Katago. Katago says that White leads by about 10 points. On the other hand, if a black stone is added at R15 like this
Then the position is considered even! There are many possible followups, here is a simple sequence which is not optimal for both players, but almost. At the end of the sequence Katago says that Black leads by 2 points, and has 52.4% winrate.
However, with the position below, White leads by 15 points!!
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| Author: | xela [ Sun Dec 08, 2019 3:14 am ] |
| Post subject: | Re: How is your positional judgement? Game 23 |
I prefer white here. Is there going to be a running battle at the top right? White can connect under at M18, or if black prevents the connection then white gets the first move in the centre. So I think this fight would favour white. What if black tries to treat the N15 stones as forcing moves and sacrifices them? Perhaps a fair trade, as the territory at top right is about equal to the sacrificed stones. But then white's top left is at least as big as black's bottom left, and white got to the bottom right corner first, so white is still ahead. |
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| Author: | Bill Spight [ Fri Dec 13, 2019 10:30 am ] |
| Post subject: | Re: How is your positional judgement? Game 23 |
Discussion of Elf's commentary In its GoGoD commentaries, after Elf estimates the winrate for one player as 88½% (73.5k rollouts). Elf assumes area scoring with 7½ pts. komi. Which player is it?White. And White won by resignation.
This was a castle game between Yasui Senchi Senkaku (Oh Senchi) (W) and Hayashi Monetsu in 1787. The game is GoGoD 1787-12-26b. Here is Elf's recommended continuation.
Black's main problem in this opening is his heavy group of floating stones. Black takes kikashi in the top right and then jumps into the center with  . Now White has a weak group. White takes kikashi in the top right corner, leaving some aji for later, and then connects underneath with  . Now  approaches the top left corner and  pincers.Earlier in the game
Up through  was standard. The jump to  is a bit unusual, offering to let White take the corner with a - g. Elf thinks that loses 3½% to par, which seems to be within Elf's margin of error.
 , threatening to push and cut, is an error, losing 13% to par. White protects and strengthens his stones with  -  .Elf's mainline variation for
threatens the standard tesuji at a. pushes, followed by hane and counter-hane.
Black plays a two step hane and then connects to make thickness, while allowing White to surround the  stones. OC, the stones have plenty of play, but this strikes me as a bold exchange for Black.Game continuation
 = There follows a string of errors, mostly minor.  loses 8% to a,  loses 11% to the keima at b,  loses 12% to a,  loses 18% to b,  loses 8½% to a,  loses 14½% to b, and  loses 6½% to par.  is tesuji, but Elf prefers the bamboo connection. Black's play is obviously heavy. is the smallest of these mistakes, but Elf has a nice variation for it.
Before connecting as in the game, White plays kikashi against Black's top right side group, cutting at  to induce  . Now Elf's mainline variation for , Black's largest error so far
Instead of making a heavier group, Black plays the keima at . After Black jumps out with . Then White sacrifices to strengthen his attack.
 tops the tree, and then White continues to attack from the center.Finally, Elf's mainline variation for
After White plays kikashi and then attacks with . jumps out, connects via the third line, and the approaches the top left corner.Elf's last two variations highlight how heavy Black's play was. |
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| Author: | dhu163 [ Mon Dec 26, 2022 11:42 am ] |
| Post subject: | Re: How is your positional judgement? Game 23 |
From the shape, both sides have played painful moves. However, B is well behind enemy lines with a group with no eyes and W can connect under the top and has Q12 in semi sente. The shape is clearly good for W. If we count 10pts for W at the top and 12 for B on the right, then B has slightly more territory. However, there is so much expansion potential from the attack with the S16 cut threatening to capture some stones. I don't think B can afford to give up those 20 ish pts on the upper side. But running will help W expand on both sides where W has a lot of potential. |
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