Tewari analysis.

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Re: Tewari analysis.

Post by hyperpape »

Kirby wrote:Is there a method to evaluate a tewari analysis that you have performed? That is, it seems possible to do it the wrong way. I like Shaddy's suggestion regarding playing "normal" moves for one side. Are there any other ways to ensure that your tewari analysis is correct?
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Re: Tewari analysis.

Post by daniel_the_smith »

Kirby wrote:Is there a method to evaluate a tewari analysis that you have performed? That is, it seems possible to do it the wrong way. I like Shaddy's suggestion regarding playing "normal" moves for one side. Are there any other ways to ensure that your tewari analysis is correct?


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Re: Tewari analysis.

Post by Bill Spight »

Kirby wrote:Tewari is kind of interesting in that respect... It makes me wonder: In go, is order important or isn't it?

I'm inclined to think that order is always very important - but then, how can we measure the benefit of tewari?


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Re: Tewari analysis.

Post by Shaddy »

Kirby wrote:Is there a method to evaluate a tewari analysis that you have performed? That is, it seems possible to do it the wrong way. I like Shaddy's suggestion regarding playing "normal" moves for one side. Are there any other ways to ensure that your tewari analysis is correct?


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Re: Tewari analysis.

Post by Redundant »

Shaddy wrote:Quis custodiet ipsos custodes?


Uh... true. I'll go with true.
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Re: Tewari analysis.

Post by RobertJasiek »

John Fairbairn wrote:Tewari [...] has virtually nothing to do with order of moves.


It is better to take a broader view: The more methods we associate with tewari the more we can apply. Of course, it is possible to call some other methods by different names like "move order analysis":) Then one needs another collective term instead of tewari though, maybe "retrospect shape and sequence analysis tools". I prefer to stick with the shorter "tewari".
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Re: Tewari analysis.

Post by RobertJasiek »

Kirby wrote:is order important or isn't it?


It is so important that it has gotten its own strategic concept "timing".

how can we measure the benefit of tewari? [...] Is there a method to evaluate a tewari analysis that you have performed?


First of all trivially: When tewari has been applied, it can or cannot have told us that something is suboptimal. It is sometimes possible to express a measure of how great the benefit it: E.g., if tewari assesses x stones to be superfluous, then the benefit is that great: x stones. Early in the game, that might be worth up to almost x handicap stones. Otherwise measuring the benefit of tewari is possible by other measurement tools like those assessing values (such as territory efficiency or mobility difference) or being analysis methods (such as local positional judgement or locally or globally applied global positional judgement). Such other tools range from simpler to much more complicated. (Details see my book.)
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Re: Tewari analysis.

Post by Kirby »

RobertJasiek wrote:...When tewari has been applied, it can or cannot have told us that something is suboptimal. ...


It's interesting that you phrase things this way. This seems to suggest the possibility that tewari is not intended as a tool to tell us if something is optimal - but can merely point out, sometimes, when something is suboptimal.

If this is the case, then there seems to be no conflict between tewari analysis and move order: move order is of great importance, and tewari can be used independently of move order to determine if something is not a good move.

In other words, it would appear that an optimal sequence will always "pass" a tewari analysis, but a sequence that passes a tewari analysis is not always optimal. Does this sound accurate?
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Re: Tewari analysis.

Post by RobertJasiek »

Kirby wrote: an optimal sequence will always "pass" a tewari analysis


No, because tewari is not developed enough yet to be always applicable successfully.
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Re: Tewari analysis.

Post by ethanb »

Redundant wrote:
Shaddy wrote:Quis custodiet ipsos custodes?


Uh... true. I'll go with true.


"Who guards the guardians?" (or watches the watchers, or polices the police, if you prefer)

It's a rhetorical question, usually used to point out some sort of injustice perpetrated by those in positions of authority. The quote is probably originally by Seneca, though I'm not going to take the time to check Wikipedia (about to leave for work.)

(EDIT: ok, I checked anyway - it's by the poet Juvenal)

In this case he's responding to Kirby's question about how to know if your tewari analysis has come up with a correct result... basically, you can't, unless you are fairly strong and already have a decent amount of practice with tewari analysis. So "who analyzes the analyzers?" :)
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Re: Tewari analysis.

Post by Redundant »

ethanb wrote:
Redundant wrote:
Shaddy wrote:Quis custodiet ipsos custodes?


Uh... true. I'll go with true.


"Who guards the guardians?" (or watches the watchers, or polices the police, if you prefer)

It's a rhetorical question, usually used to point out some sort of injustice perpetrated by those in positions of authority. The quote is probably originally by Seneca, though I'm not going to take the time to check Wikipedia (about to leave for work.)

(EDIT: ok, I checked anyway - it's by the poet Juvenal)

In this case he's responding to Kirby's question about how to know if your tewari analysis has come up with a correct result... basically, you can't, unless you are fairly strong and already have a decent amount of practice with tewari analysis. So "who analyzes the analyzers?" :)


I know the quote. I was facetiously (and rather poorly) referencing a meme.
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Re: Tewari analysis.

Post by ethanb »

Redundant wrote:I know the quote. I was facetiously (and rather poorly) referencing a meme.


My bad - I still haven't played either Portal game, so while I know the common meme from Portal, Portal 2's stuff hasn't trickled its way down the wall of pop culture into my brain yet. :)
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Re: Tewari analysis.

Post by Hazushi »

Tewari analysis can be defined as “Breaking down a position by eliminating an equal number of stones in order to analyze the efficiency of the moves”. By doing this, players get to analyse on how to make better and more efficient moves, why some variations are better than the others etc.

This can be applied to any daily chores that you do. Try to think of something that you do, step by step, and map it out on a piece of paper. Then systematically look at each step, backward, forward, and think of the steps that can be eliminated and the steps that can be combined and after eliminating and/or combining them, you still achieve the same objective of that chore.

This was said on a blog "Falling Stones are not Heavy" in the Weiqi/Go page.
Basically saying the same thing Toge said to a point but this may make it easier to understand.



Its like knowing the wanted result and knowing how to get that result through a X sequence of moves but looking at it and seeing if it can be done by following different sequence of moves that use less moves by removing the superfluous stones / bad moves or useless moves to achieve the same or better result.

I had a teacher for a bit that said, "Look at a sequence that had a desired result and count the number of moves it took you and the number of moves it took you opponent. If it took you more moves than your opponent to achieve, how ever many more stones you have vs your opponents are superfluous stones, do it again through different sequences, moves untill you get the same or better result with the same number of moves or less than your opponent." He then went to say that even understanding it that way is wrong but that it was a simple way to put it for a beginner to understand. Another way he explained to understand it is like when you are reveiwing your game at the end and looking at the better moves that could have been played in place of bad ones. Instead of playing here you play here instead because it has this effect which is better or when you see a sequence at the end and go oh if I played here then here then here instead I get a better or same result in fewer moves or such, tewari would be seeing this during the game play and using it. Thats how it was explained to me but it sounded better than how I am trying to relay it.

I have a Pro game saved some where it shows a really good example of the use of tewari, ill look for it but it may take me a day or two to find it.
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Re: Tewari analysis.

Post by Jedo »

Shaddy wrote:
Quis custodiet ipsos custodes?


I feel like everyone who's read watchmen knows that quote :D
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Re: Tewari analysis.

Post by Mef »

Kirby wrote:
RobertJasiek wrote:...When tewari has been applied, it can or cannot have told us that something is suboptimal. ...


It's interesting that you phrase things this way. This seems to suggest the possibility that tewari is not intended as a tool to tell us if something is optimal - but can merely point out, sometimes, when something is suboptimal.

If this is the case, then there seems to be no conflict between tewari analysis and move order: move order is of great importance, and tewari can be used independently of move order to determine if something is not a good move.

In other words, it would appear that an optimal sequence will always "pass" a tewari analysis, but a sequence that passes a tewari analysis is not always optimal. Does this sound accurate?



This is basically how I have always understood tewari. It will not tell you that you have played the right moves, but it can be a tool for discovering that you have played the wrong ones (=

Since the go board has no memory (barring superko), once you have completed the position, all transpositions can be evaluated equally (with respect to the final result). This means if you find a transposition where one player was playing reasonable "correct" moves, and the other player has made a mistake, it is likely a suboptimal position for that second player.

If you think of it like a mathematical sum...If moves all have a certain value (known or unknown)

-Start with position X, move to position Y via one of two sequences A or B

-We know original position X + B1a + W2a + B3a + W4a +B5a + W6a = Y and that X + B1b + W2b + B3b + W4b +B5b + W6b = Y

-If we can assume that all of white's moves are good when played (optimal ideally, but we're human), then these should for all intents and purposes cancel out. The value of the original position also cancels.

-We end up with B1a + B3a + B5a = B1b + B3b + B5b

-Evaluating the intermediate positions we show that when played, one of B1b, B3b, or B5b is suboptimal.

It must be true that somewhere either in an individual move or combination there is a suboptimal component in sequence A.


Of course all of this would depend on how well your assumptions made throughout this reasoning process hold (e.g. if white makes suboptimal moves as well, you can't cancel).
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