BlindGroup Study Journal
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Schachus
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Re: BlindGroup Study Journal
when wachting Haylee's videos I always had the impression, that tigers mouth is the main/most common reason for her to say she has good shape:)
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BlindGroup
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Re: BlindGroup Study Journal
In fairness, I could be wrong. I don't remember where I think I saw this now, but I feel like I've seen it come up a few times in the online lectures that I've watched. That said, it's also very possible that I misunderstood what was being said. That happens with frustrating frequencySchachus wrote:when wachting Haylee's videos I always had the impression, that tigers mouth is the main/most common reason for her to say she has good shape:)
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Bill Spight
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Re:
Yeah, F-18 plainly sucks.EdLee wrote:Hi BlindGroup,
Here's a case where I thought a tiger's mouth is bad shape:
post 3.
As usual, the global context matters.
But what about G-17?
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
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BlindGroup
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Re: BlindGroup Study Journal
I was wondering if someone might be able to answer two questions from a recent game where I played black?
First, I ended up in the following position and played the circle stone as shown. However, in doing so, I was worried that the marked stones needed another move. Should I have played that extra stone in support, perhaps at A? I feel like this is one of those cases in which the black stones can't be killed, but they can certainly be easily harassed. But is preventing the harassment as valuable as the shimari?
Later in the game, I faced the following board after white played the circle stone. At this point reducing white's territory in the top middle seems to be the most urgent. What is the right way to do that?
This is the best I could come up with so far:
First, I ended up in the following position and played the circle stone as shown. However, in doing so, I was worried that the marked stones needed another move. Should I have played that extra stone in support, perhaps at A? I feel like this is one of those cases in which the black stones can't be killed, but they can certainly be easily harassed. But is preventing the harassment as valuable as the shimari?
Later in the game, I faced the following board after white played the circle stone. At this point reducing white's territory in the top middle seems to be the most urgent. What is the right way to do that?
This is the best I could come up with so far:
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EdLee
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BlindGroup
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Re: BlindGroup Study Journal
I'm going to guess given just that you posed this question, that it is a bad plan 
That said, my plan was to sacrifice the black triangle stones with 2. I reasoned as follows. First, I considered the value of white's triangle stones, and decided that they were not worth much. It honestly looks like a bad cut since both the cut black groups can stand on their own. And I think white needs one more move before he can use them to surround the group in the top right. If they are not worth that much, then I didn't expect white to defend them. So, I couldn't expect moves like black A or B to be sente even if I defended against 1. Thus, the question is whether preventing white from connecting these stones and breaking through my "wall" is more valuable than enclosing the top left corner. I did't know how to do a formal calculation of this, but my guess was no. With white 1, I expected the sequence to continue as shown below, trading my influence in the bottom right for territory in the top left. Was I clearly wrong?
If I thought white would have defended the marked stones then this would be an entirely different situation. And in fact, I did deliberate about whether or not white might over-value those stones since that is very common at my level. In the end, I decided to play the game rather than the opponent.
That said, my plan was to sacrifice the black triangle stones with 2. I reasoned as follows. First, I considered the value of white's triangle stones, and decided that they were not worth much. It honestly looks like a bad cut since both the cut black groups can stand on their own. And I think white needs one more move before he can use them to surround the group in the top right. If they are not worth that much, then I didn't expect white to defend them. So, I couldn't expect moves like black A or B to be sente even if I defended against 1. Thus, the question is whether preventing white from connecting these stones and breaking through my "wall" is more valuable than enclosing the top left corner. I did't know how to do a formal calculation of this, but my guess was no. With white 1, I expected the sequence to continue as shown below, trading my influence in the bottom right for territory in the top left. Was I clearly wrong?
If I thought white would have defended the marked stones then this would be an entirely different situation. And in fact, I did deliberate about whether or not white might over-value those stones since that is very common at my level. In the end, I decided to play the game rather than the opponent.
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Schachus
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Re:
Interesting question, I thought:EdLee wrote:Hi BG, ( Just curious. ) What was your plan for?
is very painful cause you have to come back making weird shape to save your 5 stones. I think even if it is for some reason your plan to sacrifice 2 stones, exchanging 2 for 3 can only be bad for you.-
BlindGroup
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Re: Re:
This is very useful feedback.Schachus wrote:Im kinda surprised, that BG wants to give those 2 stones up, which seems like a huge success(! all blacks center potential gets destroyed at once) for white and also why you asked in the first place, so what am I missing?!
My take from what you are saying is that yet again, I'm undervaluing influence and that the loss of that influence was more valuable than getting the shimari. Is that fair?Agreed, and I did see it. However, it sounds like I underestimated the cost to me of the bad shape. Again, very good to know!PS: In your variantion, BG, also white 5 to the left of
Interesting how the answer to my original question was that I was asking the wrong question! Yet again, the unknown-unknows are more important than the known-unknowns
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EdLee
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jeromie
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Re: Re:
I don't think you even need to think of it in terms of influence versus territory. There are approximately 8 black stones on the right that don't do anything except make influence. In your plan for the cut, those stones plus the others you invest to save them end up surrounding 4-6 points of territory. That's less than one point per stone, which is really inefficient.BlindGroup wrote: My take from what you are saying is that yet again, I'm undervaluing influence and that the loss of that influence was more valuable than getting the shimari. Is that fair?
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BlindGroup
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Re: Re:
I confess I'm not used to thinking about the efficiency of stones in such a detailed way. In fact, this is the first time I've tried, and I had to read your comment several times before I thought I understood it. I think I see how locally the stones are not used efficiently. But I do not understand why the local inefficiency alone is sufficient to prefer defending against white 1 over the shimari.jeromie wrote:I don't think you even need to think of it in terms of influence versus territory. There are approximately 8 black stones on the right that don't do anything except make influence. In your plan for the cut, those stones plus the others you invest to save them end up surrounding 4-6 points of territory. That's less than one point per stone, which is really inefficient.
Here is my thought process: Let's say the position plays out as in Schachus's solution, and I'll add an extra black stone (P6) to account for the fact that I'll likely eventually need to play one to handle the aji.
Now, as you say, I've got 12 stones generating 4 points of secure territory. That's a third of a point of secure territory per stone locally -- not good.
However, at least 4 of the stones in the new wall generate influence. So, that adds between 2 and 3 points a stone -- bringing the total to 12-16 points or about 1 - 1 1/3 points per stone. Then if we also consider the shimari in the upper left. If I remember correctly from a counting book I just read that is worth 15 points of territory and some influence, say 4-6 points. So, considering both positions together, I've used 14 stones to generate 31-37 points, resulting in a rate of 2.2 - 2.6. That would argue for ignoring white 1 for the shimari, no? Or have a misunderstood or miscalculated?
[Edited: To fix the mistake pointed out by skydyr.]
Last edited by BlindGroup on Thu Sep 28, 2017 1:44 pm, edited 1 time in total.
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skydyr
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Re: Re:
Something has gone awry with your diagram, as black has a few more stones on the board than white.BlindGroup wrote:
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jeromie
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Re: BlindGroup Study Journal
Sorry, I was (am) posting from a phone and tried to get away without using diagrams.
I was talking about this: That result is unbearable for black because many stones were made inefficient, and I don't think the gain from the shimari makes up for sacrificing all of black's influence.
To answer your original question, in the middle game you can generally make most of your points by attacking. Not that you'll necessarily capture anything, but if your opponent has to save his or her stones while you make profit it is a net gain. So as you are moving into that phase of the game, it is good to assess where the weak groups on the board are. Are there an groups you can harass for profit? Are there any groups your opponent can harass for profit? The most important move is generally one that fixes your weakness or makes sure your opponent stays weak.
The black group you left to make a shimari is weak, but you can easily sacrifice one or more of those stones, so I don't think tenuki is necessarily bad. The two white cutting stones are weak and, as was pointed out, the black wall is not as strong as it looks. I think the crucial factor in the game is how those weaknesses play out.
I was talking about this: That result is unbearable for black because many stones were made inefficient, and I don't think the gain from the shimari makes up for sacrificing all of black's influence.
To answer your original question, in the middle game you can generally make most of your points by attacking. Not that you'll necessarily capture anything, but if your opponent has to save his or her stones while you make profit it is a net gain. So as you are moving into that phase of the game, it is good to assess where the weak groups on the board are. Are there an groups you can harass for profit? Are there any groups your opponent can harass for profit? The most important move is generally one that fixes your weakness or makes sure your opponent stays weak.
The black group you left to make a shimari is weak, but you can easily sacrifice one or more of those stones, so I don't think tenuki is necessarily bad. The two white cutting stones are weak and, as was pointed out, the black wall is not as strong as it looks. I think the crucial factor in the game is how those weaknesses play out.
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BlindGroup
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Re: Re:
Thanks. I meant for black to have one extra stone at P6 so that my estimate of the efficiency of those stones was reduced to account for the aji. But I mistakenly used a diagram that already had a stone at C15. I corrected the diagram.skydyr wrote:Something has gone awry with your diagram, as black has a few more stones on the board than white.BlindGroup wrote: