Gote move vs sente move in yose

RobertJasiek · **#121**

Since you want to study an example (with options for both players) initially outside my theory, you need to do it yourself or with the help of others. I lack time for such CGT application.

Gérard TAILLE · **#122**

RobertJasiek wrote:

To calculate values of a player's option, temporarily prune the tree by removing the currently not considered alternative option. This leaves two options for the opponent's start.

Your tree has options for both starting players and this makes it more complicated than any of my theory uses explicitly. Nevertheless, your questions are valid for a possibly broader understanding.

With two options for the opponent's start remaining in the pruned tree, CGT techniques must be considered. In particular, we try to detect if any of the opponent's options is dominated or reversible so can also be pruned.

If thereby the tree is without alternative options, calculate the tentative gote move value, Black's tentative sente move value (for the left sente sequence) and White's tentative sente move value (for the right sente sequence) like we always calculate gote or sente move values, respectively.

If, however, two options of the opponent remain and other reasoning cannot choose clearly, then tentative move values are undefined (so far).

If all tentative move values, tentative counts and Black's and White's follow-up move values could be calculated for a particular option, we derive the assessments of the type of the initial position for that option.

"Definitions 17 [types]
For such a local endgame, we define these types:
local gote :<=> MGOTE < MB,SENTE, MW,SENTE,
Black's local sente :<=> MW,SENTE ≥ MGOTE > MB,SENTE,
White's local sente :<=> MB,SENTE ≥ MGOTE > MW,SENTE,
Black's ambiguous :<=> MW,SENTE > MGOTE = MB,SENTE,
White's ambiguous :<=> MB,SENTE > MGOTE = MW,SENTE,
doubly ambiguous :<=> MGOTE = MB,SENTE = MW,SENTE." [22]

Again, I do NOT define the types of individual moves. I define the types of positions.

https://www.lifein19x19.com/viewtopic.p ... 45#p143245

How do you call a position for which you have MGOTE > MB,SENTE, MW,SENTE ? Is it a seki or could this position be also something else?
BTW did you define a seki position?

RobertJasiek · **#123**

Gérard TAILLE wrote:

How do you call a position for which you have MGOTE > MB,SENTE, MW,SENTE ? Is it a seki or could this position be also something else?
BTW did you define a seki position?

As previously discussed, local double sente does not exist so seki is the most prominent candidate type of positions but others might exist. Maybe two-sided ko threat regions, maybe something else.

As to seki, these definitions do not care even if tentative move values are negative. IOW, it is possible to make the theory more complicated for ko, anti-seki and whatnot.

Checking reversible can help.

The typical rules' scoring assigns the count 0 to the initial position.

EDIT: reposted due to major rewriting.

Gérard TAILLE · **#124**

Robert, in general when you use M_GOTE in your posts that means MGOTE_GOTE_OPTION. However if your post https://lifein19x19.com/viewtopic.php?p=280559#p280559 I was surprised to see

RobertJasiek wrote:

"M_GOTE > M_B,SENTE, M_W,SENTE"

where these are the tentative values of a local endgame with both players' follow-ups. Needless to say, _B uses Black's sente sequence and _W uses White's sente sequence, where sente sequence is an alternating sequence of even length. Adapting this to a local endgame with gote and sente options is straigtforward. Note that then the M_GOTE in the definition does not belong to the alternative gote options but still belongs to the sente options, that is, it is M_GOTE_OF_SENTE_OPTIONS.

In my post https://lifein19x19.com/viewtopic.php?p=280605#p280605 I used MGOTE as M_GOTE_OF_SENTE_OPTIONS and your answer was simply:

RobertJasiek wrote:

Distinguish MGOTE_GOTE_OPTION from MGOTE_SENTE_OPTION!

That is quite disturbing indeed. Does it depend on whether your are in early endgame or last endgame? What is the rule to understand what you mean by using simply MGOTE. In this difficult area where we are dealing with gote and sente options guessing what means MGOTE depending of the context is the best way for misunderstanding.

RobertJasiek · **#125**

For identifying a "sente" option, we need its internal MGOTE. Once all the details are identified, the theorems only need the MGOTE of the gote option (or / and maybe the MSENTE of the sente side).

Gérard TAILLE · **#126**

RobertJasiek wrote:

For identifying a "sente" option, we need its internal MGOTE. Once all the details are identified, the theorems only need the MGOTE of the gote option (or / and maybe the MSENTE of the sente side).

RobertJasiek wrote:

For identifying a "sente" option, we need its internal MGOTE. Once all the details are identified, the theorems only need the MGOTE of the gote option (or / and maybe the MSENTE of the sente side).

I am not sure that your way of identifying a sente option corresponds to the common understanding of a sente option for a go player.
Let's take the following example:

Click Here To Show Diagram Code: [go]$$ $$ --------------------- $$ . . . X . a O . . . | $$ . . . X X X O O O O | $$ . . . . . X . . . b | $$ . . . . . X X X X X | $$ . . . . . . . . . . |[/go]

According to your definition the black move at "a" is a sente option (and even a black move at b).
In a certain sense a mistake could be considered a sente option because the good move may remain a good threat but it is more usual to say it is only a clear mistake.
For me it is a pity you use the same wording "sente option" for such bad move. Do you consider also that a pass move is here also a sente option?

RobertJasiek · **#127**

Gérard TAILLE wrote:

Click Here To Show Diagram Code: [go]$$ $$ --------------------- $$ . . . X . a O . . . | $$ . . . X X X O O O O | $$ . . . . . X . . . b | $$ . . . . . X X X X X | $$ . . . . . . . . . . |[/go]

According to your definition the black move at "a" is a sente option (and even a black move at b). [...] it is a pity you use the same wording "sente option" for such bad move.

Identifying sente options is one analysis step. Identifying dominated options is another, or even preliminary, step.

Click Here To Show Diagram Code: [go]$$ $$ --------------------- $$ . . . X . a O . c . | $$ . . . X X X O O O O | $$ . . . . . X . . . b | $$ . . . . . X X X X X | $$ . . . . . . . . . . |[/go]

a and b are dominated by c. (From a go player's understanding. I have not verified it by CGT.) Therefore, we ignore a and b. Thus it is immaterial whether a or b are identified as sente options.

Gérard TAILLE · **#128**

RobertJasiek wrote:

Gérard TAILLE wrote:

Click Here To Show Diagram Code: [go]$$ $$ --------------------- $$ . . . X . a O . . . | $$ . . . X X X O O O O | $$ . . . . . X . . . b | $$ . . . . . X X X X X | $$ . . . . . . . . . . |[/go]

According to your definition the black move at "a" is a sente option (and even a black move at b). [...] it is a pity you use the same wording "sente option" for such bad move.

Identifying sente options is one analysis step. Identifying dominated options is another, or even preliminary, step.

Click Here To Show Diagram Code: [go]$$ $$ --------------------- $$ . . . X . a O . c . | $$ . . . X X X O O O O | $$ . . . . . X . . . b | $$ . . . . . X X X X X | $$ . . . . . . . . . . |[/go]

a and b are dominated by c. (From a go player's understanding. I have not verified it by CGT.) Therefore, we ignore a and b. Thus it is immaterial whether a or b are identified as sente options.

OK Robert, in that case let's take a small modification of your example (EDIT):

Click Here To Show Diagram Code: [go]$$B $$ --------------------------- $$ | O . X X . . a . X . X . . $$ | O O . O X . O . O X X . . $$ | . O O O . O O X O X . . . $$ | . . . O O O X X O X . . . $$ | . . . . . O X X O X . . . $$ | . . . . . O . . O X . . . $$ | . . . . . O O O O X . . . $$ | . . . . . . . . . . . . .[/go]

According to your definition, is black at "a" a black sente option?

RobertJasiek · **#129**

Black's ambiguous.

Gérard TAILLE · **#130**

RobertJasiek wrote:

Black's ambiguous.

Maybe you did not see my edit modification: instead of starting from your position (with ko) I started from Dany's position. Sorry for that Robert.

RobertJasiek · **#131**

Gérard TAILLE wrote:

Maybe you did not see my edit modification

Indeed! This I analysed:

Click Here To Show Diagram Code: [go]$$B $$ --------------------------- $$ | O . X X . . a . X . . X . $$ | O O . O X . O . O X X X . $$ | . O O O . O O X O X . . . $$ | . . . O O O X X O X . . . $$ | . . . . . O X X O X . . . $$ | . . . . . O . . O X . . . $$ | . . . . . O O O O X . . . $$ | . . . . . . . . . . . . .[/go]

Gérard TAILLE · **#132**

RobertJasiek wrote:

Gérard TAILLE wrote:

Click Here To Show Diagram Code: [go]$$ $$ --------------------- $$ . . . X . a O . . . | $$ . . . X X X O O O O | $$ . . . . . X . . . b | $$ . . . . . X X X X X | $$ . . . . . . . . . . |[/go]

According to your definition the black move at "a" is a sente option (and even a black move at b). [...] it is a pity you use the same wording "sente option" for such bad move.

Identifying sente options is one analysis step. Identifying dominated options is another, or even preliminary, step.

Click Here To Show Diagram Code: [go]$$ $$ --------------------- $$ . . . X . a O . c . | $$ . . . X X X O O O O | $$ . . . . . X . . . b | $$ . . . . . X X X X X | $$ . . . . . . . . . . |[/go]

a and b are dominated by c. (From a go player's understanding. I have not verified it by CGT.) Therefore, we ignore a and b. Thus it is immaterial whether a or b are identified as sente options.

More generaly, assume a move "a" cannot be better than a move "c" (whatever an environmment made of gote areas without follow-ups). Do you agree to call such move a bad move? My view is to avoid calling it a sente option because it is against the common understanding of a sente option. IOW I would like to reserve the wording sente option only to options that could be the best option in a certain environmment made of gote areas without followo-ups.
As an example, in your diagram above, "a" and "b" are bad moves and not sente options.

Gérard TAILLE · **#133**

Let me show you my answer to my initial question.

Click Here To Show Diagram Code: [go]$$W White to play $$ ---------------------------- $$ . . . . . . . b . . . . . | $$ . . . . . . . . . a O . . | $$ . . . . . . . X O . X O . | $$ . . X , . X . X X X . O . | $$ . . . . . . . . . . O . . | $$ . . . . . . . . . . O . . | $$ . . . . . . . . . . . . . | $$ . . . . . . . . . . . . . | $$ . . . . . . . . . . O . . | $$ . . . , . . . . . , . . . |[/go]

The question was the following : what is the best white move, white "a" or white "b"

Let's start by the white move "b". Assuming :w1:

is sente Black has very little choice and the expected sequence is the following:

Click Here To Show Diagram Code: [go]$$W count = 2 $$ --------------------------- $$ . . . . . . 2 1 3 7 . . . | $$ . . . . . . 8 4 6 5 O d . | $$ . . . . . . . X O c X O . | $$ . . X , . X . X X X . O . | $$ . . . . . . . . . . O . . | $$ . . . . . . . . . . O . . | $$ . . . . . . . . . . . . . | $$ . . . . . . . . . . . . . | $$ . . . . . . . . . . O . . | $$ . . . , . . . . . , . . . |[/go]

followed later by the exchange black "c" white "d"

Now let's take white a. Now black has a lot of options at her disposal and one of these options is the following sente sequence for white:

Click Here To Show Diagram Code: [go]$$W count = 2 $$ ---------------------------- $$ . . . . . . . 6 2 5 . . . | $$ . . . . . . . 4 3 1 O d . | $$ . . . . . . . X O c X O . | $$ . . X , . X . X X X . O . | $$ . . . . . . . . . . O . . | $$ . . . . . . . . . . O . . | $$ . . . . . . . . . . . . . | $$ . . . . . . . . . . . . . | $$ . . . . . . . . . . O . . | $$ . . . , . . . . . , . . . |[/go]

followed later by the exchange black "c" white "d"

You see the point?
White "b" is sente and lead to a position with a count +2 whitout really any choice for black
White "a" gives black a lot of options and one of them is a sequence sente for white leading to a position with count +2 without any choice for white.
Conclusion : white "a" cannot be better than white "b" because this white "a" move gives black a lot of options with one of them being equivalent to white "b". White "b" is the best choice for white. Just two counts to calculate. No need to calculate some MGOTE or MSENTE value, no need to look at other sequences.

RobertJasiek · **#134**

You guess A is sente but we do not know if it is.

Gérard TAILLE · **#135**

RobertJasiek wrote:

You guess A is sente but we do not know if it is.

No Robert I never assumed "a" is sente. I only claimed that black is ALLOWED to choose to answer "a" by the sequence shown which is sente for white. OC black may choose other options (including tenuki) and that is the reason why white "a" is not the best move.

RobertJasiek · **#136**

White A might the best if

- it is correct for Black to tenuki and

- the initial white gote with the sente follow-up is better than initially White B.

dany · **#137**

Gérard TAILLE wrote:

Let me show you my answer to my initial question.

Click Here To Show Diagram Code: [go]$$W White to play $$ ---------------------------- $$ . . . . . . . b . . . . . | $$ . . . . . . . . . a O . . | $$ . . . . . . . X O . X O . | $$ . . X , . X . X X X . O . | $$ . . . . . . . . . . O . . | $$ . . . . . . . . . . O . . | $$ . . . . . . . . . . . . . | $$ . . . . . . . . . . . . . | $$ . . . . . . . . . . O . . | $$ . . . , . . . . . , . . . |[/go]

The question was the following : what is the best white move, white "a" or white "b"

Let's start by the white move "b". Assuming :w1:

is sente

You see the point?
White "b" is sente and lead to a position with a count +2 whitout really any choice for black
White "a" gives black a lot of options and one of them is a sequence sente for white leading to a position with count +2 without any choice for white.
Conclusion : white "a" cannot be better than white "b" because this white "a" move gives black a lot of options with one of them being equivalent to white "b". White "b" is the best choice for white. Just two counts to calculate. No need to calculate some MGOTE or MSENTE value, no need to look at other sequences.

In many cases (if not most) b is gote.

KataGo experiment

Click Here To Show Diagram Code: [go]$$ White to play $$ +-----------------------+ $$ | . . . . . b . . . . . | $$ | . . . . . . . a O . . | $$ | . . , . . X O . X O O | $$ | X X X X X X X X . O . | $$ | . . . . . . . . O . O | $$ | . . . . . . . . O O O | $$ | . . . . . . . . X X X | $$ | . . . . . . . . X . X | $$ | O O O O O O O O . X . | $$ | O O , . . O X . O X X | $$ | O . . . . . . . X . . | $$ | O . . . . . . . . . . | $$ +-----------------------+[/go]

a - winning move
b - losing move

Gérard TAILLE · **#138**

dany wrote:

In many cases (if not most) b is gote.

KataGo experiment

Click Here To Show Diagram Code: [go]$$ White to play $$ +-----------------------+ $$ | . . . . . b . . . . . | $$ | . . . . . . . a O . . | $$ | . . , . . X O . X O O | $$ | X X X X X X X X . O . | $$ | . . . . . . . . O . O | $$ | . . . . . . . . O O O | $$ | . . . . . . . . X X X | $$ | . . . . . . . . X . X | $$ | O O O O O O O O . X . | $$ | O O , . . O X . O X X | $$ | O . . . . . . . X . . | $$ | O . . . . . . . . . . | $$ +-----------------------+[/go]

a - winning move
b - losing move

Sure Dany if white "b" is gote then white "a" could be the best move in the majority of cases. In that case the issue would appear completely different and it will not be the subject of this thread.
BTW Robert proposed the following position in order to assure white "b" is sente.

Click Here To Show Diagram Code: [go]$$W simplified problem $$ ---------------------------- $$ X . . . . . . . . . . . . | $$ X . . . . . . . . . O . . | $$ X . O O . . . X O . X O . | $$ X . O O . . . X X X X O O | $$ X . O O . . . X O O O O . | $$ X X X X X X X X O . . . . | $$ . . . . . . . X O . . . . |[/go]

Let's just assume white "b" is sente and see the subtle reasonning showing that in this case white "a" cannot be strictly better than white "b".

Gérard TAILLE · **#139**

RobertJasiek wrote:

White A might the best if

- it is correct for Black to tenuki and

- the initial white gote with the sente follow-up is better than initially White B.

You still did not take the point Robert. Let me explain a little more.

Click Here To Show Diagram Code: [go]$$W count = 2 $$ ---------------------------- $$ . . . . . . . b c . . . . | $$ . . . . . . . . . a O . . | $$ . . . . . . . X O . X O . | $$ . . X , . X . X X X . O . | $$ . . . . . . . . . . O . . | $$ . . . . . . . . . . O . . | $$ . . . . . . . . . . . . . | $$ . . . . . . . . . . . . . | $$ . . . . . . . . . . O . . | $$ . . . , . . . . . , . . . |[/go]

Let's assume an environment with only simple gote areas.
Let's call S1 the best sequence beginning by the white sente move "b" and let's call S2 the best sequence beginning withe white "a" black "c.
Locally these two sequences S1 ansd S2 are both sente for white with the same local result (count = -2). Considering the game itself (with the environment) the results of the games after S1 or S2 are the same.

Let's call S3 the sequence you proposed, beginning with white "a" black tenuki.

You said white "a" is better than white "b" => S3 < S1
and you said also that after white "a" the black tenuki is correct => S3 ≥ S2
Because S1 and S2 lead to the same result you have here a contradiction.

RobertJasiek · **#140**

Simply speaking, your proof is correct! Congratulations on the implied proposition and its suitable example!

Gote move vs sente move in yose

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