About the first question in the thread: capturing in the corner is 22 points in gote. It is a huge move, I would definitely play there with white.
If white plays hane instead, I would definitely play there with black.
Which is bigger, A or B?
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Bill Spight
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Re: Which is bigger, A or B?
Kirby wrote:I'd like to clarify something regarding this comment, which I don't get.
Here, white takes gote. But a play at 'x' is white's privilege - it's sente for white, but gote for black.
So later in the game, we can assume that white will get to push:
So that will be the final position.
Contrast this with the hane:
is playing at 'y' white's privilege? I'm not so sure.
You don't think that 'y' is White's sente?
If things play out as suggested with the throw-in variation that was provided here, this was the final variation:
Black has one more point at 'w' in this variation, and the option of later taking the ko.
I don't understand how we can assume the jump at 'y', above, since it's not clear to me that this is black's privilege, given the throw-in variation.
So I don't completely understand the comment that the sagari is 7-8 points less than the hane. It only makes sense to me if we assume the jump at 'y', but I don't see how this will happen given the throw-in variation.
Well, that throw-in variation makes White saving his group sente. And a large sente, at that, worth about 25 points. The variation where Black tenukis and allows White to continue with the jump to "y", makes White saving his group gote. If the jump to "y" is sente, that gote gains only about 17 points. But it is true that I did not work out the White follow-up after "y". I assumed that it was worth more than 8 points, because the Black area is open, and because of my knowledge of the value of another one space jump on the edge in more enclosed situations, and because the traditional value of the monkey jump agrees with my calculations. But I did not calculate the follow-ups, and the follow-ups after that, etc., which would have been necessary to get a precise value. Your objection has made me reconsider. One thing is that, because the Black territory is open, Black does not have as good a reply to the jump to "y" as when the territory is more closed. So maybe the jump to "y" is not sente, because it has gained so much already.
Maybe the White follow-up gains only 6 points or so. (I hardly think it can gain less. My admittedly imperfect influence function estimates the gain at about 8 points. It assumes that all the stones are alive, which does not seem too far off base here.) Anyway, on the assumption that the jump to "y" is gote, with a follow-up that gains only 6 points, the hane gains about 16 points instead of 17 points. The hane is still clearly better than the sagari, and it is gote. The Adkins Principle:
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— Winona Adkins
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Re: Which is bigger, A or B?
Well, I don't know if 'y' is sente or not. I was confused because I thought the throw-in variation was the better one, and if so, the sagari is not worse than the hane since it reduces black by more points on the top.
But it sounds like you're saying that the throw-in variation is worse since it lets white live in sente. I suppose that's true, but it's not intuitive to me since black captures white's hane stone.
Also, I wasn't objecting so much as asking for clarification. I know almost nothing about the endgame.
But it sounds like you're saying that the throw-in variation is worse since it lets white live in sente. I suppose that's true, but it's not intuitive to me since black captures white's hane stone.
Also, I wasn't objecting so much as asking for clarification. I know almost nothing about the endgame.
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Bill Spight
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Re: Which is bigger, A or B?
Kirby wrote:Well, I don't know if 'y' is sente or not. I was confused because I thought the throw-in variation was the better one, and if so, the sagari is not worse than the hane since it reduces black by more points on the top.
But it sounds like you're saying that the throw-in variation is worse since it lets white live in sente. I suppose that's true, but it's not intuitive to me since black captures white's hane stone.
Also, I wasn't objecting so much as asking for clarification. I know almost nothing about the endgame.
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White is alive, right?The Adkins Principle:
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— Winona Adkins
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Re: Which is bigger, A or B?
Yeah, I don't dispute that it's alive in sente. Maybe I just didn't realize why it was a bad variation. For example, if black just leaves it:
I don't know if white will get the jump at 'y' or if black will get the block at 'z'. Maybe the point is, since 'y' is probably sente, we can assume white will get 'y'?
Intuitively, it seems that black's followup to 'z' is sente, so it would be most likely that black would get 'z'.
If that's the case, I'd compare this diagram for the hane:
to this variation for the descent:
The descent is easier for me to understand, since the ko isn't involved, so maybe I'm not making a fair comparison.
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Bill Spight
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Re: Which is bigger, A or B?
Kirby wrote:
Yeah, I don't dispute that it's alive in sente. Maybe I just didn't realize why it was a bad variation. For example, if black just leaves it:
I don't know if white will get the jump at 'y' or if black will get the block at 'z'. Maybe the point is, since 'y' is probably sente, we can assume white will get 'y'?
Intuitively, it seems that black's followup to 'z' is sente, so it would be most likely that black would get 'z'.
If that's the case, I'd compare this diagram for the hane:
to this variation for the descent:
The descent is easier for me to understand, since the ko isn't involved, so maybe I'm not making a fair comparison.
The last diagram is gote, not sente.
The Adkins Principle:
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— Winona Adkins
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Re: Which is bigger, A or B?
Bill Spight wrote:The last diagram is gote, not sente.
True. It lives in gote.
In the throw-in variation, black will probably tenuki at this point in the game, leaving the position here:
Now, there are two possibilities I see here:
- If black plays at 'y', white can live in sente (assuming black can't afford to fight a ko if white plays at the marked intersection).
- Black never gets the chance to play at 'y', and white plays at 'z' (or 'v' if white feels ambitious about the ko situation).
The first option is not black's privilege since it will end in gote (unless black can win all ko threats, I guess?). The second one may be white's privilege, depending on whether it's sente, I guess?
So can we assume that the second possibility is the one that's more likely to happen under optimal play?
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Re: Which is bigger, A or B?
I guess there's also the situation where there is no throw-in at all:
I guess black should probably play at least 'y', because if white ignores to play sente somewhere else, black captures the hane stone in sente.
So if black plays 'y', white can either answer or not answer:
1.) If white doesn't answer, black captures the hane stone in sente, and it's questionable as to whether the hane was better than living in gote - maybe it is, if the other sente is big enough (?)
2.) If white answers, black will almost certainly tenuki, but later cut at the marked spot, I guess:
which is probably sente, I guess, but is more in points than sagari, anyway, so maybe that shows it's better.
I think I'm confusing myself at this point, but maybe I'll take a break and think about it a little bit more later.
I guess black should probably play at least 'y', because if white ignores to play sente somewhere else, black captures the hane stone in sente.
So if black plays 'y', white can either answer or not answer:
1.) If white doesn't answer, black captures the hane stone in sente, and it's questionable as to whether the hane was better than living in gote - maybe it is, if the other sente is big enough (?)
2.) If white answers, black will almost certainly tenuki, but later cut at the marked spot, I guess:
which is probably sente, I guess, but is more in points than sagari, anyway, so maybe that shows it's better.
I think I'm confusing myself at this point, but maybe I'll take a break and think about it a little bit more later.
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Bill Spight
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Re: Which is bigger, A or B?
Kirby wrote:I guess there's also the situation where there is no throw-in at all:
I guess black should probably play at least 'y', because if white ignores to play sente somewhere else, black captures the hane stone in sente.
So if black plays 'y', white can either answer or not answer:
1.) If white doesn't answer, black captures the hane stone in sente,
If White doesn't answer, Black kills.
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Re: Which is bigger, A or B?
Bill Spight wrote:
If White doesn't answer, Black kills.
Yes, good point
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Re: Which is bigger, A or B?
Kirby, if you have doubts about the one space jump after ignored hane being sente, why do you think push after your descent is sente?
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Re: Which is bigger, A or B?
Uberdude wrote:Kirby, if you have doubts about the one space jump after ignored hane being sente, why do you think push after your descent is sente?
Well, the two are similar in that regard. What's most unclear to me is the throw-in variation with the ko. If black has ko threats, practically speaking, it seems black may be able to block at 'y' in sente.
But I guess I think it's more likely that white lives in sente since black has to eventually take the ko.
I guess I lean toward thinking the hane is better than descending, but I can't say I have my head wrapped around the position.
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Re: Which is bigger, A or B?
Kirby wrote:Uberdude wrote:Kirby, if you have doubts about the one space jump after ignored hane being sente, why do you think push after your descent is sente?
Well, the two are similar in that regard. What's most unclear to me is the throw-in variation with the ko. If black has ko threats, practically speaking, it seems black may be able to block at 'y' in sente.
But I guess I think it's more likely that white lives in sente since black has to eventually take the ko.
I guess I lean toward thinking the hane is better than descending, but I can't say I have my head wrapped around the position.
Hmmmm, you still seem to be confused. So if white hanes then if black blocks directly white is still not alive (a17 still kills, the exchange didn't help white):
So to be consistent with the first move white would connect and live. This leaves a 1st line cut of some fairly large endgame value that black may or not defend with his sente (probably not in this game).
If white hanes and black throws in then white takes. White is now alive, the throw in helped white live as a17 no longer kills.
Black now has sente, but white is already alive. Black could choose to place a stone at y (which he already had if he didn't throw in!) and it looks like below.
Usually black doesn't need to worry much about the ko cut, because taking the ko is sente for him to kill the corner, so it likely ends up looking like this after he takes the ko and later white takes back and black defends. So black closed the top, but took gote to do it. It's like you decided to defend the cutting point after diagram 2, but maybe another move is bigger.
So if you want to compare with the descend, you need to compare with a white living in gote variation in which black didn't help white live, so:
vs:
In the first white's endgame follow up is cutting and taking a load of points, let's say black plays 2 to stop white breaking in there:
vs the smaller reduction:
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Bill Spight
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Re: Which is bigger, A or B?
Just to follow up a bit on Uberdude's analylis.
Globally, we agree that Black plays tenuki now, rather than let White live with sente. Let's do a little tewari.
If White lives with the sagari and later takes his local sente with
, is obviously correct.
is incorrect. But it duplicates the position in the first diagram, which indicates that 
in that diagram is wrong.
Globally, we agree that Black plays tenuki now, rather than let White live with sente. Let's do a little tewari.
If White lives with the sagari and later takes his local sente with
, is obviously correct. is incorrect. But it duplicates the position in the first diagram, which indicates that in that diagram is wrong.The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
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— Winona Adkins
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Everything with love. Stay safe.
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Kirby
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Re: Which is bigger, A or B?
Uberdude wrote:Hmmmm, you still seem to be confused.
Oh, I don't doubt it!
Actually, though, your analysis mostly makes sense, but what hangs me up is this (bold part added by me):
Uberdude wrote:
Usually black doesn't need to worry much about the ko cut, because taking the ko is sente for him to kill the corner, so it likely ends up looking like this after he takes the ko and later white takes back and black defends. So black closed the top, but took gote to do it. It's like you decided to defend the cutting point after diagram 2, but maybe another move is bigger.
Since the ko situation is not clear to me, it's not clear to me that black has to defend at the marked stone in the position above.
So it's not as straightforward to me as a position that is 100% gote for black.
That's why the descent is much easier for me to understand:
Black clearly ends in gote, so I can see the end result.
But here:
Is the marked intersection necessary? It's not as clear to me.
So if we assume that black must defend this spot and gets gote, then I can compare it apples-to-apples with the descent variation where I know black gets gote.
Since it seems theoretically possible for black to block off in sente here due to an unknown ko situation, it's hard for me to feel completely satisfied.
In practice, the ko is probably too heavy on black, so it's basically as good as black having gote.
But it just bugs me a little bit that it seems like it could be sente.
I guess I just have to accept that black cannot afford to take sente in this situation, and if I treat that as an absolute, then we can say that white absolutely lives in sente if black does the throw-in.
And in that case, I guess doing the throw-in is not a good move, and not a variation we should compare.
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