Values of moves

[Bill Spight]

Alright, I give up. it was a stupid question.

What was a stupid question? Certainly not your original one.

Maybe the easiest way to get a ballpark figure is harder than you had hoped, but it still is within your capabilities.

But the place to start is with evaluating local positions. (At least for humans. ) Endgame books show how to do that.

Once you can make ballpark estimates of local positions, it is not difficult to make ballpark estimates of plays. And even if you don't make ballpark estimates of plays, you can make ballpark estimates of the results of your reading.

[Bill Spight]

There is no such thing as consistently good endgame without effort of value calculation and comparison.

Well worth repeating.

[Bill Spight]

What is difficult is that even Big and Not Big depend on sente and followup.

The difficulty of figuring out sente was the main reason, IMHO, the go programmers failed to come up with a good evaluation function in four decades of collective effort. If they had, I doubt if today's bots would be using winrates.

However, humans understand the concept of sente, if fuzzily. Sente is important for evaluating local positions, because after a sente is played with sente, the resulting position has the same value as the initial position, and is easier to count. If you start with evaluating local positions, you will develop your sense of sente.

One question though: How would you go about deciding between a sente move and a big gote move?

There's good news and bad news. Let's start with the bad news.

Bad news 1). You may want to save the sente for a ko threat.

Silver lining. If you are even thinking about playing the sente, that is probably not the case.

Bad news 2). You can only be sure that the big gote is right if it is quite big. Using the common way of counting — which I do not recommend, but which you probably are already using — the gote normally has to be bigger than both the sente move plus its threat.

Silver lining. A gote that big has probably already been played.

Now for the good news.

Good news 1). If you are not saving the sente as a ko threat (probably the case) and the threat of the sente is bigger than the big gote, so that your opponent should answer the sente, play the sente.

Good news 1a). That is very likely to be the case.

These are the basics. If we consider the rest of the board, other considerations apply.

There is a rule of thumb about doubling the size of a sente (using, cough, the common way of counting) in order to compare it with a gote. This actually applies to reverse sente. You can normally save a sente to use as a possible ko threat until just before your opponent will play the reverse sente. That's why it is useful for sente, as well.

[Bill Spight]

You said you will not have time to calculate during a game. I guess the usual thing is to calculate examples outside your games, and by that train your intuition to better and better guess the values quickly during a game. It's like with tsumego. The more you do them the better you get at guessing how to kill or live in a fast game.

I agree with the idea of non-play practice. Especially reviewing your own endgames.

But as for calculation, parrots can "count" up to 6 at a glance, i. e., tell the difference between 5 items and 6. So can humans. Even if we're not Rainman. And if all we want is ballpark estimates, getting up to 30 in a second or two is not hard. We can also multiply. E. g., there's a territory bounded by stones on the third line up to the side star point. 2x10 = 20. Bingo!

[Bill Spight]

It's better to make a hanging connection after the hane:

$$B
$$ +-------------------+
$$ | . . . 3 9 5 7 8 . |
$$ | . . . . 1 2 6 0 . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . . . . |
$$ | . . , X . . , . . |
$$ | . . . . . O . O . |
$$ | . . . . . . . . . |
$$ +-------------------+

Click Here To Show Diagram Code

[go]$$B
$$ +-------------------+
$$ | . . . 3 9 5 7 8 . |
$$ | . . . . 1 2 6 0 . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . . . . |
$$ | . . , X . . , . . |
$$ | . . . . . O . O . |
$$ | . . . . . . . . . |
$$ +-------------------+[/go]

Assuming the other player doesn't want to risk the ko, then you get more points.

Hmm... something seems off ?
And tenuki (above variation) causes different calculations.

$$B var 2
$$ +--------------------
$$ | . . . . 5 3 4 . . |
$$ | . . . . 1 2 6 . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . . . . |
$$ | . . , X . . , . . |
$$ | . . . . . O . O . |
$$ | . . . . . . . . . |
$$ +--------------------

Click Here To Show Diagram Code

[go]$$B var 2
$$ +--------------------
$$ | . . . . 5 3 4 . . |
$$ | . . . . 1 2 6 . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . . . . |
$$ | . . , X . . , . . |
$$ | . . . . . O . O . |
$$ | . . . . . . . . . |
$$ +--------------------[/go]

If simply replies with descend, then locally B has fewer points than B's hane & solid connect in var 2.

$$B var 3
$$ +--------------------
$$ | . . . 3 . 4 . . . |
$$ | . . . . 1 2 . . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . . . . |
$$ | . . , X . . , . . |
$$ | . . . . . O . O . |
$$ | . . . . . . . . . |
$$ +--------------------

Click Here To Show Diagram Code

[go]$$B var 3
$$ +--------------------
$$ | . . . 3 . 4 . . . |
$$ | . . . . 1 2 . . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . . . . |
$$ | . . , X . . , . . |
$$ | . . . . . O . O . |
$$ | . . . . . . . . . |
$$ +--------------------[/go]

This tiger's mouth is after hane, but leads to yet different calculations
( but locally B still seems worse off than var 2 ):

$$B var 4
$$ +--------------------
$$ | . . . 5 6 3 4 . . |
$$ | . . . . 1 2 . . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . . . . |
$$ | . . , X . . , . . |
$$ | . . . . . O . O . |
$$ | . . . . . . . . . |
$$ +--------------------

Click Here To Show Diagram Code

[go]$$B var 4
$$ +--------------------
$$ | . . . 5 6 3 4 . . |
$$ | . . . . 1 2 . . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . . . . |
$$ | . . , X . . , . . |
$$ | . . . . . O . O . |
$$ | . . . . . . . . . |
$$ +--------------------[/go]

When making an estimate during play, I reckon the ko to be Black sente (unless I know better) and reply to it thus.

$$B var 5
$$ +--------------------
$$ | . . . 5 . 3 4 . . |
$$ | . . . . 1 2 6 . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . . . . |
$$ | . . , X . . , . . |
$$ | . . . . . O . O . |
$$ | . . . . . . . . . |
$$ +--------------------

Click Here To Show Diagram Code

[go]$$B var 5
$$ +--------------------
$$ | . . . 5 . 3 4 . . |
$$ | . . . . 1 2 6 . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . . . . |
$$ | . . , X . . , . . |
$$ | . . . . . O . O . |
$$ | . . . . . . . . . |
$$ +--------------------[/go]

This is obviously no worse for White than the hanetsugi.

[Pio2001]

What is the easiest way to determine a rough value of a move in order to compare alternatives. I am more interested in "ballpark" than "correct." For starters, how about this: black to play: What are a, b and c worth?

$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . a . . . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . b . . |
$$ | . . , X . . , . . |
$$ | . . . . c O . O . |
$$ | . . . . . . . . . |
$$ +-------------------+

Click Here To Show Diagram Code

[go]$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . a . . . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . b . . |
$$ | . . , X . . , . . |
$$ | . . . . c O . O . |
$$ | . . . . . . . . . |
$$ +-------------------+[/go]

Hi Daal,
A first easy rule is to play first the moves that are very sente, then the reverse sente, then the double gote.

To know if a move is sente, you have to look where the sequence can stop. For example :

$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . a b . |
$$ | . . , X . . . . . |
$$ | . . . . . O . O . |
$$ | . . . . . . . . . |
$$ +-------------------+

Click Here To Show Diagram Code

[go]$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . a b . |
$$ | . . , X . . . . . |
$$ | . . . . . O . O . |
$$ | . . . . . . . . . |
$$ +-------------------+[/go]

In the above diagram, thinking that a is sente because White must answer b is a mistake !... because then, Black must answer White b.

$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . a . . . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . 1 2 . |
$$ | . . , X . . 3 . . |
$$ | . . . . . O . O . |
$$ | . . . . . . . . . |
$$ +-------------------+

Click Here To Show Diagram Code

[go]$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . a . . . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . 1 2 . |
$$ | . . , X . . 3 . . |
$$ | . . . . . O . O . |
$$ | . . . . . . . . . |
$$ +-------------------+[/go]

Here, Black 3 is locally sente. But is it really sente ? White could ignore Black 3 and take a instead.

On the other hand, for me, a is really sente, because, in the diagram below, after move 2, black can stop there and play b

$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . 1 2 . . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . b . . |
$$ | . . , X . . . . . |
$$ | . . . . c O . O . |
$$ | . . . . . . . . . |
$$ +-------------------+

Click Here To Show Diagram Code

[go]$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . 1 2 . . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . b . . |
$$ | . . , X . . . . . |
$$ | . . . . c O . O . |
$$ | . . . . . . . . . |
$$ +-------------------+[/go]

c is reverse sente, so it can be played next.

$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . 1 2 . . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . 3 4 . |
$$ | . . , X . . 5 6 . |
$$ | . . . . 7 O . O . |
$$ | . . . . . . . . . |
$$ +-------------------+

Click Here To Show Diagram Code

[go]$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . 1 2 . . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X . 3 4 . |
$$ | . . , X . . 5 6 . |
$$ | . . . . 7 O . O . |
$$ | . . . . . . . . . |
$$ +-------------------+[/go]

If you are counting continuations, when black and white continuations are both gote, you can assume that the continuation is halfway between them. If one of the continuations only is sente, assume that it will be the one being played.

Another trick : if you have prisoners that need to be counted in parallel, you can switch to area counting (just count the number of intersections that change colour if White starts instead of Black, stones included). I'm not sure of the implications. Robert Jasiek talks about it in his book Endgame 2, but I have not yet read this chapter.

[Gomoto]

$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . 1 . . . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X 5 3 6 . |
$$ | . . , X 8 . 4 . . |
$$ | . . 7 2 0 O . O . |
$$ | . . . 9 . . . . . |
$$ +-------------------+

Click Here To Show Diagram Code

[go]$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . 1 . . . . |
$$ | . . , X . O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , . O . . |
$$ | . . . . X 5 3 6 . |
$$ | . . , X 8 . 4 . . |
$$ | . . 7 2 0 O . O . |
$$ | . . . 9 . . . . . |
$$ +-------------------+[/go]

$$B
$$ +-------------------+
$$ | . . . . 5 3 4 . . |
$$ | . . . 9 X 2 6 . . |
$$ | . . , X 8 O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , 7 O . . |
$$ | . . . 1 X X X O . |
$$ | . . , X O . O . . |
$$ | . . X O O O . O . |
$$ | . . . X 0 . . . . |
$$ +-------------------+

Click Here To Show Diagram Code

[go]$$B
$$ +-------------------+
$$ | . . . . 5 3 4 . . |
$$ | . . . 9 X 2 6 . . |
$$ | . . , X 8 O , . . |
$$ | . . . X . O . . . |
$$ | . . X . , 7 O . . |
$$ | . . . 1 X X X O . |
$$ | . . , X O . O . . |
$$ | . . X O O O . O . |
$$ | . . . X 0 . . . . |
$$ +-------------------+[/go]

$$B
$$ +-------------------+
$$ | . . . . X X O . . |
$$ | . . . X X O O . . |
$$ | . . , X O O , . . |
$$ | . . . X 2 O 4 . . |
$$ | . . X . 3 X O . . |
$$ | . . . X X X X O . |
$$ | . . , X O . O . . |
$$ | . . X O O O . O . |
$$ | . . 1 X O . . . . |
$$ +-------------------+

Click Here To Show Diagram Code

[go]$$B
$$ +-------------------+
$$ | . . . . X X O . . |
$$ | . . . X X O O . . |
$$ | . . , X O O , . . |
$$ | . . . X 2 O 4 . . |
$$ | . . X . 3 X O . . |
$$ | . . . X X X X O . |
$$ | . . , X O . O . . |
$$ | . . X O O O . O . |
$$ | . . 1 X O . . . . |
$$ +-------------------+[/go]

[daal]

Alright, I give up. it was a stupid question.

What was a stupid question? Certainly not your original one.

Maybe the easiest way to get a ballpark figure is harder than you had hoped, but it still is within your capabilities.

But the place to start is with evaluating local positions. (At least for humans. ) Endgame books show how to do that.

Once you can make ballpark estimates of local positions, it is not difficult to make ballpark estimates of plays. And even if you don't make ballpark estimates of plays, you can make ballpark estimates of the results of your reading.

Yes, indeed harder than I hoped. I have started once again to look into miai counting. I watched [url="https://www.youtube.com/watch?v=ZbgQ9jvhZS0"]a video[/url] that was made during the 2012 go congress, and it explained some of the basic ideas, but I think it takes a lot of practice to be able to do during a game. Do you perhaps know of a set of exercises with easy problems? I think that might be a good place to start

[RobertJasiek]

The youtube videos on miai counting or Sensei's miai values list are not an easy start. If you want problems rather than theory with easy examples, easy problems rather than kos and whatnot, more than the few problems in O's book and no Japanese book (I think John mentioned some, but I do not know whether the problems and answers are easy), you have two options: dig for Bill's problems here (not that many, not always easy, often with difficult extras such as value trees) - or wait a few months. If you cannot wait, what prevents you from reading examples as if they were problems?

[Kirby]

I'll tell you anyway. I am not good at calculating, and am even worse at calculating under pressure. I am 100% positive that any method that promises a correct evaluation is too hard for me to use in a game situation. For this reason, I am looking for something that I am able to use, with the hope that it would provide a right answer more often than not, and that this would be better than just guessing.

What sticks out to me here is the reference to look for a (quick) way to get to the "right answer".

For quite some time, I was depressed about AlphaGo. Regardless of study, talent, or effort, anyone can download the latest go ai and be capable of getting the right answer for a given position. What's the point then? Isn't coming up with the answer the essence of go?

I maintain that it is.

But for awhile, I missed something: it's not the answer that's the essence of go. It's COMING UP with the answer.

In other words, the mental process of evaluating and identifying a move is enjoyable and gives go meaning, independently of where you happen to place your stone.

So I suggest that, while it may be possible to come up with a shortcut to give you a semi-accurate answer, it may not give the same satisfaction as thinking deeply about a position, and coming to a solution- even if it's wrong!

Just my thoughts about it at the moment. YMMV

[daal]

The youtube videos on miai counting or Sensei's miai values list are not an easy start.

I have to disagree. I found this video, in which the lecturer took questions from the audience, to be quite a good introduction. Here are two of the diagrams from the lecture that were on a level that I could follow:

$$B examples from the video
$$ +---------------------+
$$ | . . . X . a O . . . |
$$ | . . . X X X O . . . |
$$ | . . , . . . . , . . |
$$ | . . . . . . . . . . |
$$ | . . . . . . . . . . |
$$ | . . . . . . . . . . |
$$ | . . . . . . . . . . |
$$ | . . , . . . . , . . |
$$ | . . . X X X X O . . |
$$ | . . . X . . b O . . |
$$ +---------------------+

Click Here To Show Diagram Code

[go]$$B examples from the video
$$ +---------------------+
$$ | . . . X . a O . . . |
$$ | . . . X X X O . . . |
$$ | . . , . . . . , . . |
$$ | . . . . . . . . . . |
$$ | . . . . . . . . . . |
$$ | . . . . . . . . . . |
$$ | . . . . . . . . . . |
$$ | . . , . . . . , . . |
$$ | . . . X X X X O . . |
$$ | . . . X . . b O . . |
$$ +---------------------+[/go]

If you want problems rather than theory with easy examples, easy problems rather than kos and whatnot, more than the few problems in O's book and no Japanese book (I think John mentioned some, but I do not know whether the problems and answers are easy), you have two options: dig for Bill's problems here (not that many, not always easy, often with difficult extras such as value trees) - or wait a few months.

I am looking forward to your next book, but I have neither O's book nor any Japanese ones, and Bill's problems are usually over my head.

If you cannot wait, what prevents you from reading examples as if they were problems?

This is a fine idea. Where might one find more such easy examples?

[John Fairbairn]

daal

To show you are not alone:

O Meien starts his discussion of values with the following position.



He adds:

How much territory does Black have on the edge at the 1-1 point? Not many people give the right answer to this question. I was very surprised to learn that this was so. Over 80% of people answered with something like:

“It hasn’t been settled whether Black will capture or White will connect, so it must be impossible to put a number on how much territory he has.”
Even among superior dan players the answers have been more or less the same. I have been surprised but just had to accept that this is the reality. That is why I thought about writing this book; because something exists which is common knowledge for us pros and some high dan amateurs, yet to the majority of amateurs it is a case of “No answer can be given.”

But none of them has any reason to feel awkward. The point is, it is just a problem of whether or not they know how to count.

He further adds:

When counting territory, it may be ideal to be good at go, but basically it has nothing to do with go strength.

O's explanation is as follows ('calculation' is being used in the sense of primary-school arithmetic, not reading).

You will have understood that if Black captures he gets 2 points and if White connects Black gets 0 points. But this still leaves the question “How many points of Black territory are there in Problem A?” unresolved. It would not be wrong to say “2 points or 0 points” but that would not be appropriate as a “calculation.”

So, consider first which is higher, the probability of Diagram 1 occurring or the probability of Diagram 2?

The answer is obvious, isn’t it: 50% for each. In other words, the probability of Black’s territory being 2 points or being 0 points is 50% in each case. By halving the total number of points we get 1 point, and this is the answer that applies to the initial question posed. That is, at the point in time of Problem A we can count the Black territory as 1 point.

OK? I think you can see that there was absolutely no go strength involved in that. We calculate the respective numbers of points for when Black plays and White plays and if their probabilities are equal, we divide the total by two.

All other positions follow the same method at heart even if they look more complicated. As he puts it, "The method of calculation does not change, so there is nothing to worry about."

True enough, but there is a next step. The territory count is not the same as "the value of the move" (O's key term).

As regards Black t2, the meaning of this move is definitely not “a territory of 0 points becomes 2 points.” Do understand completely that it really means a 1-point territory becomes a territory with 2 points. I am being long-winded but I want to impress this on you. In other words, “the value of the move” is 1 point.

Another example for practice:



How much territory does Black have in the extreme corner?

O says:

If Black throws in at t2 the two White stones are captured as they are, and so Black’s territory is 5 points (3 points + two prisoners). No problem thus far, but …

When you considered White’s connection at t2, did you do a “!”?

In all the problems so far when White connected, Black’s territory simply came out as 0 points. But now we have the new occurrence of a White territory of 1 point.

Bothersome. We can’t do a calculation in such cases? Of course we can. We can produce a precise figure in the form of “X points.” Let us try looking at it as follows.

If we wish to express the fact that White has a territory of 1 point from Black’s point of view, what do we do. You’ve already got it, haven’t you? That’s right: we assume that a White territory of 1 point equals a Black territory of minus one point. This concept of “minus X points” is important, and if we can think that way, the following steps can be done in exactly the same way as Problems A ~ C [not shown here].

[1] Black’s territory in Diagram 7 is 5 points and Black’s territory in Diagram 8 is -1 point.

[2] The probabilities for Diagrams 7 and 8 are equal, and so:

(5 + {-1}) ÷ 2 = 2.

This is the answer. In other words, at the point in time of Problem D [shown here], in this area we can calculate that “Black has a territory of 2 points.”

One of the many nice things about O's book is that he explains everything without relying on terms like reverse sente (though he does mention them in passing), and you don't need to know whether there's an R in the month to know which meaning sente has. You certainly don't get bombarded with rule sets and even counting of kos is explained clearly and not as a conjuring trick. Fractions are mostly swept under the carpet (but they are there if you want them). The mathematics is of the level I enjoyed as a 6-year-old in Miss Middleton's class.

I've already said it several times, but I really do think any half serious go player needs O's book on his bookshelf.

[RobertJasiek]

daal, the video gives the first step (if you understood it, fine) but it does not really enable walking. I had known the first step but the video did not help me to proceed.

You find easy examples by looking at only the easy examples of the miai values list (skip all earlier, small value ko examples because they are difficult) but you might find them useless because calculations are mostly missing. Much more useful are easy examples with detailed step by step calculations and their explanations but, since this is not the books forum, I am prohibited from answering in this thread.

[daal]

(5 + {-1}) ÷ 2 = 2.

I get the same answer, but I don't quite follow the math. It seems to me that the span of points between black getting the play and white getting it is 6, not 4, so the value of the position should lie between 5 and minus one, in other words 2 points for black. I arrive at this by dividing the 6 by 2 which equals 3, and subtracting that from black's 5 (or adding it to white's minus one).

In any case, the book seems to explain the method in a way that even I can follow, Thanks for the excerpt. I take it the book is only available in Japanese?

[Bill Spight]

I found this video, in which the lecturer took questions from the audience, to be quite a good introduction.

Do you mean Kyle Blocher's video? It's excellent!