Shuei endgame question

For lessons, as well as threads about specific moves, and anything else worth studying.
RobertJasiek
Judan
Posts: 6272
Joined: Tue Apr 27, 2010 8:54 pm
GD Posts: 0
Been thanked: 797 times
Contact:

Re: Shuei endgame question

Post by RobertJasiek »

The black follower can be a local gote, ambiguous, local sente or something else. The white follower can be a local gote, ambiguous, local sente or something else. The initial position of a local endgame can be a local gote, ambiguous, local sente or something else. This is so regardless of whether the black follower is a local gote, ambiguous, local sente or something else.

We know that our black follower is a local sente. We still have to determine the status of the initial local position BEFORE THE BLACK MOVE. You call the move Black 1, Bill calls it Black 4 and rushes ahead claiming it to be ambiguous. However, we need to verify that it is indeed ambiguous.
User avatar
Knotwilg
Oza
Posts: 2432
Joined: Fri Jan 14, 2011 6:53 am
Rank: KGS 2d OGS 1d Fox 4d
GD Posts: 0
KGS: Artevelde
OGS: Knotwilg
Online playing schedule: UTC 18:00 - 22:00
Location: Ghent, Belgium
Has thanked: 360 times
Been thanked: 1021 times
Contact:

Re: Shuei endgame question

Post by Knotwilg »

I'll give it a try. I'm sensing that I'm about to understand miai counting after all these years (or maybe I said so 10 years ago, I'm getting old in many ways)
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . O X . X X . . . X W . . . O . |
$$ | . . . O X . X O O X X . e . . , O . . |
$$ | . . . O X . O d O O . . . O . . . . . |
$$ | . O . O X X X O X O O . O . . . X . . |
$$ | O S O O X . O X X O X . X O O . . . . |
$$ | . O X X X X O O X X X . X X O . . O O |
$$ | 1 X . . X O X X O . . O . X O O O X . |
$$ | C X X X O O O X X X X O . O X X X . X |
$$ | . . . X X O . O O . X X . . . X . X . |
$$ | . . . X O O O . O X . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Let's first assume this move is local gote. We know Black's follower is a sente move with value 1. So we don't count the squared point for White while we do count the circled point for Black. The count of this position is +1
Click Here To Show Diagram Code
[go]$$W
$$ | . . . . O X . X X . . . X W . . . O . |
$$ | . . . O X . X O O X X . e . . , O . . |
$$ | . . . O X . O d O O . . . O . . . . . |
$$ | . O . O X X X O X O O . O . . . X . . |
$$ | O S O O X . O X X O X . X O O . . . . |
$$ | 3 O X X X X O O X X X . X X O . . O O |
$$ | 1 X . . X O X X O . . O . X O O O X . |
$$ | 2 X X X O O O X X X X O . O X X X . X |
$$ | . . . X X O . O O . X X . . . X . X . |
$$ | . . . X O O O . O X . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
We further simplify by assuming White needs to answer at :w3:. This time the count is -1 due to the squared point. The position has count 0 (taking the squared and circled point, here :b2:, into account) and the miai value is 1. In other words, :w1: is a 1 point gote.

Now let's check our assumption.
Click Here To Show Diagram Code
[go]$$W
$$ | . . . . O X . X X . . . X W . . . O . |
$$ | . . . O X . X O O X X . e . . , O . . |
$$ | . . . O X . O d O O . . . O . . . . . |
$$ | . O . O X X X O X O O . O . . . X . . |
$$ | O S O O X . O X X O X . X O O . . . . |
$$ | 5 O X X X X O O X X X . X X O . . O O |
$$ | 1 X . . X O X X O . . O . X O O O X . |
$$ | 3 X X X O O O X X X X O . O X X X . X |
$$ | 4 6 . X X O . O O . X X . . . X . X . |
$$ | . . . X O O O . O X . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
First consider that :w1: in itself was gote. The follower destroys 2 points in sente. So, Mg = (1-(-1-2))/2 = 4/2 = 2 while F = 2. So this is ambiguous. Black can choose to answer or not.
Click Here To Show Diagram Code
[go]$$W
$$ | . . . . O X . X X . . . X W . . . O . |
$$ | . . . O X . X O O X X . e . . , O . . |
$$ | . . . O X . O d O O . . . O . . . . . |
$$ | . O . O X X X O X O O . O . . . X . . |
$$ | O S O O X . O X X O X . X O O . . . . |
$$ | . O X X X X O O X X X . X X O . . O O |
$$ | 1 X . . X O X X O . . O . X O O O X . |
$$ | 2 X X X O O O X X X X O . O X X X . X |
$$ | . . . X X O . O O . X X . . . X . X . |
$$ | . . . X O O O . O X . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Next we must verify :b2: can remain unanswered, which would make :w1: a sente move. Black's follower, capturing :w1: is sente and Black can leave the ko behind. The value of that follower is 5/3 which would make White's move a 1 - 5/3 sente, which is absurd.

So, :b2: must be answered.
Click Here To Show Diagram Code
[go]$$B
$$ | . . . . O X . X X . . . X W . . . O . |
$$ | . . . O X . X O O X X . e . . , O . . |
$$ | . . . O X . O d O O . . . O . . . . . |
$$ | . O . O X X X O X O O . O . . . X . . |
$$ | O S O O X . O X X O X . X O O . . . . |
$$ | . O X X X X O O X X X . X X O . . O O |
$$ | 1 X . . X O X X O . . O . X O O O X . |
$$ | . X X X O O O X X X X O . O X X X . X |
$$ | . . . X X O . O O . X X . . . X . X . |
$$ | . . . X O O O . O X . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Although technically ambiguous from White's perspective, I would call :b1: a 1 point gote, with the benefit of simplicity and not being essentially wrong.
User avatar
Knotwilg
Oza
Posts: 2432
Joined: Fri Jan 14, 2011 6:53 am
Rank: KGS 2d OGS 1d Fox 4d
GD Posts: 0
KGS: Artevelde
OGS: Knotwilg
Online playing schedule: UTC 18:00 - 22:00
Location: Ghent, Belgium
Has thanked: 360 times
Been thanked: 1021 times
Contact:

Re: Shuei endgame question

Post by Knotwilg »

And repeating my evaluation of F in the original diagram:
Click Here To Show Diagram Code
[go]$$W
$$ ---------------------------------------
$$ | . . . . . . X X . X 2 1 . . 7 5 6 . . |
$$ | . . . . O O O X X . X O . . 3 X 8 . . |
$$ | . . . O . O X . X X O O . . O X . . . |
$$ | . . . , O . b . . O . . O S O , X . . |
$$ | . . X . . . . O . O O O O . . X . . . |
$$ | . . . O . . . . O X X X . . . . X X X |[/go]
This is our reference, :w1: being sente and :w3: having a sente follower. We count 6 points for White here, the squared point depends on what happens in the middle.
Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ | . . . . . . X X . X X O . . S C C . . |
$$ | . . . . O O O X X . X O . 3 1 X C . . |
$$ | . . . O . O X . X X O O . . O X . . . |
$$ | . . . , O . b . . O . . O . O , X . . |
$$ | . . X . . . . O . O O O O . . X . . . |
$$ | . . . O . . . . O X X X . . . . X X X |[/go]
Black makes 3 points here, destroying 3 of White's reference 6. The follower destroys 3 more and makes another point with 50% probability.

Mg = (6+3,5/2)/2 = 3,875, F = 3,5 so it is a 3,875 gote.
User avatar
Knotwilg
Oza
Posts: 2432
Joined: Fri Jan 14, 2011 6:53 am
Rank: KGS 2d OGS 1d Fox 4d
GD Posts: 0
KGS: Artevelde
OGS: Knotwilg
Online playing schedule: UTC 18:00 - 22:00
Location: Ghent, Belgium
Has thanked: 360 times
Been thanked: 1021 times
Contact:

Re: Shuei endgame question

Post by Knotwilg »

Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ | . . . . . . X X . X . . . . . . . . . |
$$ | . . . . O O O X X . X O . . . X . . . |
$$ | . . . O . O X . X X O O . . O X . . . |
$$ | . . . , O . . . . O . . O . O , X . . |
$$ | . . X . . . . O . O O O O . . X . . . |
$$ | . . . O . . . . O X X X . . . . X X X |
$$ | . . . . . . . . X . . b . . . O O O X |
$$ | . . O . O . . . . . . X O O . . . . O |
$$ | . . . . O X . X X . C S X W . . . O . |
$$ | . . . O X . X O O X X c 1 a . , O . . |
$$ | . . . O X . O . O O . 2 . O . . . . . |
$$ | . O . O X X X O X O O . O . . . X . . |
$$ | . X O O X . O X X O X . X O O . . . . |
$$ | . O X X X X O O X X X . X X O . . O O |
$$ | . X . . X O X X O . . O . X O O O X . |
$$ | . X X X O O O X X X X O . O X X X . X |
$$ | . . . X X O . O O . X X . . . X . X . |
$$ | . . . X O O O . O X . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
In this reference position after Black's sente move of :b1: we count the circled point. Other border points like the squared one are likely to become neutral due to White's moves like B or C. Black's A is sente too.
Click Here To Show Diagram Code
[go]$$W
$$ ---------------------------------------
$$ | . . . . . . X X . X . . . . . . . . . |
$$ | . . . . O O O X X . X O . . . X . . . |
$$ | . . . O . O X . X X O O . . O X . . . |
$$ | . . . , O . . . . O . . O . O , X . . |
$$ | . . X . . . . O . O O O O . . X . . . |
$$ | . . . O . . . . O X X X . . . . X X X |
$$ | . . . . . . c . X . . b . . . O O O X |
$$ | . . O . O . . . . . . X O O . . . . O |
$$ | . . . . O X . X X . 6 5 X W . . . O . |
$$ | . . . O X . X O O X X c 1 S S , O . . |
$$ | . . . O X . O . O O . 2 . O . . . . . |
$$ | . O . O X X X O X O O 3 O . . . X . . |
$$ | . X O O X . O X X O X . X O O . . . . |
$$ | . O X X X X O O X X X . X X O . . O O |
$$ | . X . . X O X X O . . O . X O O O X . |
$$ | . X X X O O O X X X X O . O X X X . X |
$$ | . . . X X O . O O . X X . . . X . X . |
$$ | . . . X O O O . O X . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
If White forestalls Black's sente, she makes the 2 squared points, captures a stone and destroys the Black point circled in the previous diagram, here at :b6: Later, White C is also sente, so we can count the point under the captured stone too. The remainder of the border remains similar as in Black's sente position.

Hence this is not such a difficult move to evaluate: it's a 5 point move and Black's sente.
kvasir
Lives in sente
Posts: 1040
Joined: Sat Jul 28, 2012 12:29 am
Rank: panda 5 dan
GD Posts: 0
IGS: kvasir
Has thanked: 25 times
Been thanked: 187 times

Re: Shuei endgame question

Post by kvasir »

I found this topic yesterday. I find it hard to follow and there doesn't seem to be a clear conclusion.

It appears only Knotwilg tried to work it out. I don't mind calculating values but my critique is that calculating values for 7 different endgames is unrealistic, and for most people intuition or internalized principles are needed to reach a good conclusion. I think it is a good study so I gave it some thought too.

I'd consider this as my mainline candidate, probably informed by something I read above. Don't get your hopes up because my endgame is terrible but even worse outside of actual games, i.e. it is hard to get into the right mood and solving endgames one move at a time seems less error prone than posting sequences in chat or on forums.

Is this very wrong?
Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ | . . . . . . X X . X . . . . . . . . . |
$$ | . . . . O O O X X . X O . . 8 X . . . |
$$ | . . . O . O X . X X O O . . O X . . . |
$$ | . . . , O . . . . O . . O . O , X . . |
$$ | . . X . . . . O . O O O O . . X . . . |
$$ | . . . O . . a . O X X X . . . . X X X |
$$ | . . . . . . . . X . . . . . . O O O X |
$$ | . . O . O . . . . . . X O O . . . . O |
$$ | . . . . O X . X X . . . X O . . . O . |
$$ | . . . O X . X O O X X . 5 . . , O . . |
$$ | . . . O X . O . O O 4 2 6 O . . . . . |
$$ | 9 O . O X X X O X O O 1 O . . . X . . |
$$ | . X O O X . O X X O X 3 X O O . . . . |
$$ | 7 O X X X X O O X X X . X X O . . O O |
$$ | . X . . X O X X O . . O . X O O O X . |
$$ | . X X X O O O X X X X O . O X X X . X |
$$ | . . . X X O . O O . X X . . . X . X . |
$$ | . . . X O O O . O X . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Let me explain my thought process.
I am deliberately inexact and fuzzy about the value calculations because I think my intuition or internalized principles are often better than my value calculations.

I saw :b1: in Bill's post and it is obviously best.

I calculated :b7: to be 7.5-9.5 compared to less than 8 for :w8: and it is hard for the a area to be bigger than :b7: or :w8: in practice.

I think a could be bigger than :b9: but it is not sente and likely is smaller. I naively think I should test :b9: before creating ko threats in the center and not playing :b9: early is likely to lead to white considering to play reverse sente.

For a I try to calculate an average value for moves in that area. I get 2-3 points average per move. This needs to be multiplied by 2 for direct comparison. I don't find this calculation to be particularly useful and trying is the first step to failure. I also find it hard to believe that the first move is so big. My internalized principles tell me that I am not in hurry to play in this area because it takes many moves to reduce and there are alternatives that are clearly bigger or clearly sente but eventually this is the biggest area.
Post Reply