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 Post subject: Re: Average value of a move
Post #11 Posted: Tue Mar 19, 2013 7:11 am 
Judan

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As others have said, the size of moves generally decreases over the course of the game but there can be huge (100+) spikes if there are large unsettled groups fighting each other. This is when moves are very urgent. Until the endgame (and in fact not even then, though by then territory is the primary concern), you should not only be thinking in terms of territory but also the strength and weakness of groups. If a move is just 8 points that's not very exciting in the opening or middlegame. But if it is 8 points and makes your / your opponents' groups stronger/weaker, aims at further things in the future etc. then that is much more interesting and likely to be a good move.

A special variant of Go termed Environmental Go was played in which there was a stack of cards valued at 20 points, 19.5, 19, 18.5 etc which could be taken instead of playing a move on the board. Studying that game will help you understand the question here. As you will see they take cards in bunches when there is nothing urgent on the board, but when there is some urgent fighting going on the size of moves increases so they will play a lot of moves without taking the cards.

I posed a whole-board question on these forums recently in which there was a big (~15 points) gote move available during the opening/middlegame. It was interesting in the differing opinions even among the stronger players here about whether to take the money: Magicwand and logan said yes, me, Bill Spight and shapenaji said no.


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 Post subject: Re: Average value of a move
Post #12 Posted: Tue Mar 19, 2013 7:56 am 
Oza
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PeterPeter wrote:
Suppose an opportunity for a monkey jump arises in the first 20 moves. A monkey jump is usually worth around 8 points, I think?


It's not just about the 8 (9?) points. First, there's the question of gote and sente. If you do it in good style, the monkey jump should almost always end in sente (i.e., you have the initiative after the reduction). A sente move is your privilege. You can choose to play it very early, or you can wait and wait. Normally waiting is better. If he gets to block the monkey jump, so what? He had to give up his sente to do it. If he played it too early, he might have even lost points in the bargain. But by biding your time, you avoided helping him solidify his group. This may have allowed you use the threat of an invasion to do serious damage elsewhere. Even if there is no aji to preserve, you may end up using the monkey jump as a ko threat.

Second, there's the question of attack and defense. How much eyespace, exactly, does the group you're monkey-jumping into have? Is he barely scraping by with two eyes after the first jump? Can he ignore the first jump and give you a second jump on the inside? Or is he completely safe even if he lets you reduce his side territory to nothing? In other words, does the monkey jump have any relevance to the middle game, or is it purely an endgame (boundary-play) kind of move? If the latter, you're more likely to get egg on your face if you try to play it too early. If the former, the monkey jump may be an urgent move that gives you the upper hand in the center, as well as a few points on the side.

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 Post subject: Re: Average value of a move
Post #13 Posted: Tue Mar 19, 2013 8:15 am 
Judan

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jts wrote:
...Second, there's the question of attack and defense. How much eyespace, exactly, does the group you're monkey-jumping into have? Is he barely scraping by with two eyes after the first jump? Can he ignore the first jump and give you a second jump on the inside? Or is he completely safe even if he lets you reduce his side territory to nothing? In other words, does the monkey jump have any relevance to the middle game, or is it purely an endgame (boundary-play) kind of move? ...


Sometimes a monkey jump can be even worse: when he answers it can increase the eyeshape of the group you jumped into compared to doing nothing! So you just helped your opponent live instead of keeping the option of killing him later if you get stronger on the outside.

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 Post subject: Re: Average value of a move
Post #14 Posted: Tue Mar 19, 2013 8:38 am 
Oza
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Uberdude wrote:
jts wrote:
...Second, there's the question of attack and defense. How much eyespace, exactly, does the group you're monkey-jumping into have? Is he barely scraping by with two eyes after the first jump? Can he ignore the first jump and give you a second jump on the inside? Or is he completely safe even if he lets you reduce his side territory to nothing? In other words, does the monkey jump have any relevance to the middle game, or is it purely an endgame (boundary-play) kind of move? ...


Sometimes a monkey jump can be even worse: when he answers it can increase the eyeshape of the group you jumped into compared to doing nothing! So you just helped your opponent live instead of keeping the option of killing him later if you get stronger on the outside.

And on the other hand, you can see a horribly embarrassing game of mine where W made a monkey jump to add an eye! :blackeye: :blackeye: :blackeye:

[deleted]


Last edited by jts on Thu Feb 23, 2017 7:30 pm, edited 1 time in total.
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 Post subject: Re: Average value of a move
Post #15 Posted: Tue Mar 19, 2013 8:48 am 
Judan

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@jts, I don't know if I can get to see the monkey jump as I need to clear the blood from my eyes after r13 and p12 ;-)

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 Post subject: Re: Average value of a move
Post #16 Posted: Tue Mar 19, 2013 8:54 am 
Oza

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jts wrote:
And on the other hand, you can see a horribly embarrassing game of mine where W made a monkey jump to add an eye! :blackeye: :blackeye: :blackeye:


Didn't white already have two eyes at O18 and P12?

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 Post subject: Re: Average value of a move
Post #17 Posted: Tue Mar 19, 2013 8:58 am 
Judan

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skydyr wrote:
Didn't white already have two eyes at O18 and P12?


No, o18 is a false eye.

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 Post subject: Re: Average value of a move
Post #18 Posted: Tue Mar 19, 2013 9:00 am 
Oza

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Uberdude wrote:
skydyr wrote:
Didn't white already have two eyes at O18 and P12?


No, o18 is a false eye.


Ah. I can tell this is true because I seem to be looking at it through my own false eye :oops:

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 Post subject: Re: Average value of a move
Post #19 Posted: Tue Mar 19, 2013 9:01 am 
Honinbo

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PeterPeter wrote:
This is something I have been puzzling over.

What is the average value of a move, as the game progresses?


Nobody knows. :)

We now think that the first move gains around 14 points. But 50 years ago (and for a long time before) we thought that it gained around 10 points.

Quote:
My first line of thinking was that komi is 6.5, and an endgame move (around move 200) might be 1 or 2, so you could draw a straight line between those points. But that doesn’t sound right (too low).


It is too low. Komi does not equal the size of a play. But even if you drew a straight line between 14 points at move 1 and 0 points at move 240 or so, you would surely not even be close for much of the game. As others have pointed out, the size of a move increases for sustained periods during middle game battles.

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My reason for wanting to know is that, say on move 100 I find a move worth 5 points, should I be pleased to play it without a lot more thought, or spend the time looking for something better?


First, I don't know what you mean by a move worth 5 points. For one thing, there are two main ways of valuing points. One is by how much a move gains on average, the other is how much a move gains for one player plus how much a move gains for the other. The 14 point value uses the first way. For instance, if all a move does is to capture 5 stones that the opponent could save in one move, it is worth 5 points by the first way, 10 points by the second. And you may have yet a different idea in mind.

Second, at move 100 you are very likely to be in the middle game, and the moves will be worth much more than 5 points by either way.

Third, of course you should spend some time looking for something better, even if it is only a few seconds.

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Last edited by Bill Spight on Tue Mar 19, 2013 9:32 am, edited 1 time in total.
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 Post subject: Re: Average value of a move
Post #20 Posted: Tue Mar 19, 2013 9:25 am 
Honinbo

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PeterPeter wrote:
Let me come at it from a different angle.

Suppose an opportunity for a monkey jump arises in the first 20 moves. A monkey jump is usually worth around 8 points, I think?

Well, obviously you would not want to play it straightaway.

Roughly when in the game would you expect to start considering it as a serious option? (Or blocking it, if you are the one who left it open)


The size of the monkey jump depends upon the surroundings. Sometimes it is sente, sometimes it is not.

If you want to estimate the move number to play it, my first thought is that that is a question for the database guys. :) This page on Sensei's Library is relevant. http://senseis.xmp.net/?PointPopularityByMoveNumber

My interpretation is that the popularity of plays in the center at move 105 indicates the middle game. There is not much territory in the center, so I expect that plays there are made to attack and defend groups. The fact that play shifts back to the second line at move 142 indicates the large endgame stage. (That is later than John Fairbairn reports. That could be because the pros do not actually note the number of the move when they start playing the endgame -- who does? --, and are misestimating it, or it could be because the largest endgame plays are often in the center. Edit: It could also be because large yose plays may be made in the middle game, or even the opening.) By move 199 play starts moving to the first line. Most of those plays are not monkey jumps, and are smaller. So monkey jumps would probably be played earlier.

Based on that one page, my guess for the typical move range for a monkey jump would be between move 140 or so and move 180 or so, depending upon the surroundings.

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 Post subject: Re: Average value of a move
Post #21 Posted: Tue Mar 19, 2013 9:38 am 
Honinbo

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jts wrote:
And on the other hand, you can see a horribly embarrassing game of mine where W made a monkey jump to add an eye! :blackeye: :blackeye: :blackeye:



Too bad White didn't resign after move 25. ;)

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Post #22 Posted: Tue Mar 19, 2013 5:27 pm 
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PeterPeter wrote:
I know, but playing a game in online timeframes, and with 200 empty points to evaluate in a typical middle game position, a rule of thumb comes in handy :) .
Umm... actually, no. I'd say it's not handy; it's detrimental to your Go, IMO. :)


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Post #23 Posted: Tue Mar 19, 2013 5:42 pm 
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EdLee wrote:
PeterPeter wrote:
I know, but playing a game in online timeframes, and with 200 empty points to evaluate in a typical middle game position, a rule of thumb comes in handy :) .
Umm... actually, no. I'd say it's not handy; it's detrimental to your Go, IMO. :)

Yes, I think you might be right.

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 Post subject: Re: Average value of a move
Post #24 Posted: Tue Mar 19, 2013 8:25 pm 
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The average value of a move doesn't help much as a guideline. For example when I play a slow, solid move, I know for a fact that later on in the game the stone that made no territory whatsoever is going to help me make lots of territory later.

Calculating the average value of a move as the game progresses leaves you blind to what's going on on the board. Stones have function, groups have strength. You're making plans and so is your opponent. That's what matters.

At the end of a close game, each stone you played will have returned a value of around 0.5 points anyway. There's enough to worry about without trying to find out whether or not you've met quota every move. If you really are worried, do what the pros do: count relative territory every chance you get. :D

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