How is your positional judgement?

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Bill Spight
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Re: How is your positional judgement?

Post by Bill Spight »

Game 3.

As always, area scoring with 7½ pt. komi.

Elf estimates a winrate of 92.7% (31k playouts) after :w30:. Which player is it?
Click Here To Show Diagram Code
[go]$$Wcm30 Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . X X O O . . . |
$$ | . . X . . O . . . . . X O O X . O . . |
$$ | . X . O . . . . . , . . O X . X . . . |
$$ | . X O . . . . . . . . . . . . . . O . |
$$ | . X X O . . . . . . . . . . . X . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . X . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Enjoy! :)
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At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.
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Knotwilg
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Re: How is your positional judgement?

Post by Knotwilg »

Since the ladder works for White, Black should probably use a squeezing tactic like this:
Click Here To Show Diagram Code
[go]$$B Squeeze
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . X X O O . . . |
$$ | . . X . . O . . . . . X O O X . O . . |
$$ | . X . O . . . . . , . 7 O X 0 X . . . |
$$ | . X O . . . . . . . . 1 2 4 6 . . O . |
$$ | . X X O . . . . . . . a 3 5 8 X . . . |
$$ | . . . O . . . . . . . . . . 9 . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . X . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
White can probably keep things a little easier like this:
Click Here To Show Diagram Code
[go]$$B Squeeze
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . X X O O . . . |
$$ | . . X . . O . 9 . . . X O O X 6 O . . |
$$ | . X . O . . . . . , . 5 O X 4 X . . . |
$$ | . X O . . . . . . . . 1 3 2 . 8 . O . |
$$ | . X X O . . . . . . . . . 7 . X . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . X . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Can Black play :b7: and force :w8:?
Truth is: I don't know.

Perhaps White needs to play the ko:
Click Here To Show Diagram Code
[go]$$B Squeeze
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . X X O O . . . |
$$ | . . X . . O . . . . . X O O X . O . . |
$$ | . X . O . . . . . , 3 2 O X 0 X . . . |
$$ | . X O . . . . . . . . 1 4 6 7 . . O . |
$$ | . X X O . . . . . . . a 5 8 . X . . . |
$$ | . . . O . . . . . . . . . 9 . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . b . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . X . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
This is difficult to judge. If Black connects at A, White ends the ko and Black still has defects. If Black plays a ko threat at B, then White destroys Black at the top with a double atari at A.

Overall I'm inclined to say White, but I can't find a graceful variation.
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Bki
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Re: How is your positional judgement?

Post by Bki »

Both side have a solid corner which are roughly equivalent. Similarly white's left is about the same as black's lower side to me. So this would come down to the fight in the top right. The ladder doesn't work, so black is split in two groups while white only have one. But the white group is an eyeless clump of stone, while one of black's group can make some life on the edge and the other has some sort of shape. And it's black sente. At the same time, white is stronger in the area than black is due to the white group to the left and most ladder will tends to go in white's favor.

I feel that black will tend to a group while pressuring white. White meanwhile will strengthen himself in the sequence, and then black will have to look after his other groups. Then white will have a relatively safe group in the center, and either can get an attack against one of the two groups, or get sente to play elsewhere. Honestly I don't feel such a position would be a 90% game for me if I were to play it, but white can't possibly have a lost game so by this magnificent meta argument white is better :).
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Bill Spight
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Re: How is your positional judgement?

Post by Bill Spight »

Game 3.

A no komi game between Go Seigen 8 dan (W) and Sakata 7 dan, GoGoD 1950-07-04a. The usual caveats about no komi games apply. For Sakata to take Black with no komi was the usual handicap; given the dan difference Sakata would take White ⅓ of the time. Elf estimates White's winrate at 92½% with a komi of 7½ points. Even with no komi, White, Go Seigen, won by resignation.
Click Here To Show Diagram Code
[go]$$Wcm30 Go Seigen (W) - Sakata, no komi
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . X X O O . . . |
$$ | . . X . . O . . . . . X O O X . O . . |
$$ | . X . O . . . . . , . . O X . X . . . |
$$ | . X O . . . . . . . . . . . . . . O . |
$$ | . X X O . . . . . . . . . . . X . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . X . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
According to Elf, both players made a number of small mistakes early in the game, which may be explained by the shared beliefs about the opening at the time. The first sizable mistake was :b19:, which may have also been a mistake with no komi.
Click Here To Show Diagram Code
[go]$$Bcm19 Failure to sacrifice? Loss of 20%
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . X . . O . . . . . . . O . . . . . |
$$ | . X . O . . . . . , . . . . . X . . . |
$$ | . X O . . . . . . . . . . . . . . . . |
$$ | . 1 X O . . . . . . . . . . . X . . . |
$$ | . . . 2 . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . X . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
:b19: caught me by surprise. When I was learning go the sacrificial hane at 20 was joseki. It appears that :b19: allowed White to make too much outside strength with :w20:.
Click Here To Show Diagram Code
[go]$$Bcm19 Sacrifice. Main line.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . X . . O . . . . . . . O . . . . . |
$$ | . X . O . . . . . , . . . . . X . . . |
$$ | . X O . . . . . . . . . . . . . . . . |
$$ | . 3 X O 4 . . . . . . . . . . X . . . |
$$ | . . 2 1 . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . B . . . |
$$ | . . . . . X . . . B . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
:w22: The ladder works now, but Black has many ladder breakers near the :bc: stones.
Click Here To Show Diagram Code
[go]$$Bcm23 Main line, continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . X . . O . . . . . . . O . . 8 . . |
$$ | . X . O . . . . . , . 7 . . . X 9 . . |
$$ | . X O . . . . . . . . . 5 . . . . . . |
$$ | . X X O O . . . . . . . . . . X . . . |
$$ | . . O X . . . . . . . . . 0 . . . . . |
$$ | . . O . . . . . . . . . . . 4 . 2 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . 6 a , 3 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . X . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
:b23: At the time, 25 was usual, but today's bots have devalued the sides.

:w28: is good shape. a would allow a double peep.
Click Here To Show Diagram Code
[go]$$Bcm29 Failure to sacrifice, loss of 12½%
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . 1 X O O . . . |
$$ | . . X . . O . . . . . X O O X . O . . |
$$ | . X . O . . . . . , . . 2 X . X . . . |
$$ | . X O . . . . . . . . . . . . . . O . |
$$ | . X X O . . . . . . . . . . . X . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . X . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
According to Elf, :b29: loses 12½%. OC, the subsequent fight is complicated, and there is no komi, so :b29: was not necessarily a mistake.
Click Here To Show Diagram Code
[go]$$Bcm29 Sacrifice variation
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . 4 . . . . . |
$$ | . . . . . . . . . . . 3 2 X O O . . . |
$$ | . . X . . O . . . . . X O O X . O . . |
$$ | . X . O . . . . . , . . 1 X . X . . . |
$$ | . X O . . . . . . 5 . . . . . . . O . |
$$ | . X X O . . . . . . . . . . . X . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . X . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
This sacrifice lowers White's winrate estimate to 80%.
Click Here To Show Diagram Code
[go]$$Bcm31 Elf's continuation, I
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . X X O O . . . |
$$ | . . X . . O . . . . . X O O X . O . . |
$$ | . X . O . . . . . , . 1 O X . X 7 . . |
$$ | . X O . . . . . . . 5 4 2 . . . . O . |
$$ | . X X O . . . . . . . 3 6 . . X . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . X . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Click Here To Show Diagram Code
[go]$$Wcm38 Elf's continuation, II
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . X X O O . . . |
$$ | . . X . . O . . . . 4 X O O X . O 2 . |
$$ | . X . O . . . . . . 3 X O X . X X . . |
$$ | . X O . . . . . . 5 X O O . . . . O . |
$$ | . X X O . . . . . . 1 X O . . X . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . X . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
White sacrifices the corner for central strength. :)
Click Here To Show Diagram Code
[go]$$Bcm31 Knotwilg's idea
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . b X X O O . . . |
$$ | . . X . . O . . . . . X O O X a O . . |
$$ | . X . O . . . . . , 5 4 O X 6 X 3 . . |
$$ | . X O . . . . . . . . 1 . 2 . . . O . |
$$ | . X X O . . . . . . . . . . . X . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . X . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Elf considers Knotwilg's idea for :b31: and gives the above variation, with :b33: pushing into the corner. Next if Black a, White b, I reckon.

The remaining diagrams show the continuation in the actual game.
Click Here To Show Diagram Code
[go]$$Bcm31 Actual game continuation
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . X X O O . . . |
$$ | . . X . . O . . . . . X O O X . O . . |
$$ | . X . O . . . . . , 3 . O X . X . . . |
$$ | . X O . . . . . . . . . 2 1 . . 9 O . |
$$ | . X X O . . . . . 7 5 . 4 . . X . 0 . |
$$ | . . . O . . . . . . 6 . . . . . . . . |
$$ | . . O . . . . . . . . . . . . 8 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . X . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
The fight continues into the center. :w38: severely attacks Black's small group in the top right.
Click Here To Show Diagram Code
[go]$$Bcm41 Small life, but with sente
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . X X O O . 4 . |
$$ | . . X . . O . . . 6 . X O O X 3 O . . |
$$ | . X . O . . . . . 0 X . O X . X 1 2 . |
$$ | . X O . . . . . . . . . O X 5 . X O . |
$$ | . X X O . . . . . X X . O . . X . O . |
$$ | . . . O . . . . . . O 7 8 . . . . . . |
$$ | . . O . . . . . . . . 9 . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . X . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Since Black lives with sente, he manages to put some pressure on White.
Click Here To Show Diagram Code
[go]$$Bcm51 White starts to develop the right side
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . X X O O . O . |
$$ | . . X . . O . 9 . O . X O O X X O . . |
$$ | . X . O . . . . 0 O X . O X . X X O . |
$$ | . X O . . . . . . 1 . . O X X . X O . |
$$ | . X X O . . . . . X X . O . . X . O . |
$$ | . . . O . . . . . . O X O . . . . . . |
$$ | . . O . . . . . . . . X 2 . . O . . . |
$$ | . . . . . . . . . . . 3 . . . . . . . |
$$ | . . . , . . . . . , . 7 6 4 . , . . . |
$$ | . . . . . . . . . . . 8 5 . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . X . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
White pushes on into the right side. the center battle continues. Elf gives Black a 2% chance to win. Go Seigen won by resignation after White 234. (Sakata hated to resign.)
Last edited by Bill Spight on Wed Nov 13, 2019 10:17 am, edited 10 times in total.
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Re: How is your positional judgement?

Post by Bill Spight »

Game 4.

As always, assume area scoring with a 7½ pt. komi. After :w30: Elf gives one player an estimated 88% winrate with 144.2k playouts. Which player is it?
Click Here To Show Diagram Code
[go]$$Wc Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . O . . . . . X . . . . . X O . . |
$$ | . . . , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . O . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . X X O . . . . X . . . |
$$ | . . . , . . . . X O O . . . . , . . . |
$$ | . . . O . . . . O X X O O . . X . . . |
$$ | . . . . . . . . O . . X X . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Enjoy!
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Knotwilg
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Re: How is your positional judgement?

Post by Knotwilg »

This is easier than the ones before. Black needs to save 2 cutting stones with an empty triangle. Then White pushes up, cutting off 3 stones from Black's area of development. This game is White's.
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Joaz Banbeck
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Re: How is your positional judgement?

Post by Joaz Banbeck »

Black plays K2 and wins.

My general assessment is that white has two weak groups, black has one.
Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . O . . . . . X . . . . . X O . . |
$$ | . . . , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . O . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . X X W . . . . X . . . |
$$ | . . . , . . . . X W W . . . . , . . . |
$$ | . . . O . . . . W X X O O . . X . . . |
$$ | . . . . . . . . W X . X X . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
I don't claim that the following diagrams are conclusive, nor even accurate. I post them to illustrate the general idea that when white saves one group, the other is in trouble. I'll leave it to LZ to figure out the exact tactics.
Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . O . . . . . X . . . . . X O . . |
$$ | . . . , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . O . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . 1 . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . X X O . . . . X . . . |
$$ | . . . 3 2 . . . X O O . . . . , . . . |
$$ | . . . O . . 4 . W X X O O . . X . . . |
$$ | . . . . . 6 5 . W X . X X . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . O . . . . . X . . . . . X O . . |
$$ | . . . , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . O . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . 1 . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . 0 X X O . . . . X . . . |
$$ | . . . 3 2 . 8 9 X O O . . . . , . . . |
$$ | . . . O . . 4 7 W X X O O . . X . . . |
$$ | . . . . . 6 5 . W X . X X . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . O . . . . . X . . . . . X O . . |
$$ | . . . , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . O . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . 1 . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . X X O . . . . X . . . |
$$ | . . . 3 2 . 8 . X O O . . . . , . . . |
$$ | . . . O . 7 4 . W X X O O . . X . . . |
$$ | . . . . . 6 5 . W X . X X . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
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Dusk Eagle
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Re: How is your positional judgement?

Post by Dusk Eagle »

Click Here To Show Diagram Code
[go]$$Wcm30 Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . B B O O . . . |
$$ | . . X . . O . . . . . B O O B . O . . |
$$ | . X . O . . . . . , . . O B . B . . . |
$$ | . X O . . . . . . . . . . . . . . O . |
$$ | . X X O . . . . . . . . . . . B . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . X . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
I prefer white. These black stones will be a liability.
Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . O . . . . . X . . . . . X O . . |
$$ | . . . , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . O . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . X X O . . . . X . . . |
$$ | . . . , . . . . X O O . . . . , . . . |
$$ | . . . O . . . . O X X O O . . X . . . |
$$ | . . . . . . . . O B . X X . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
I prefer white. Black has to play :bc:, then white has more solid territory as well as sente for the fight on the bottom side.

But I would never assign a ~90% win rate to one side in these positions like Elf is so keen to.
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Re: How is your positional judgement?

Post by Knotwilg »

Reacting to Joaz:
Black plays K2 and wins.
My general assessment is that white has two weak groups, black has one.
I see it differently: one of these two White groups are two low stones, providing useful aji but expendable. The other one, which is the one to save will put pressure on Black's 3 stones, which are not expendable, while impacting Black's only area for growth.
Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . O . . . . . X . . . . . X O . . |
$$ | . . . , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . O . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . 3 . . . . . . . . |
$$ | . . . O . . . . X X O . . . . X . . . |
$$ | . . . . . . . . X O O . . . . , . . . |
$$ | . . . O . b 4 . W X X O O a . X . . . |
$$ | . . . . . . b . W X 2 X X . . . . . . |
$$ | . . . . . . . . . 1 . . . . . . . . . |
$$ ---------------------------------------[/go]
B4 probably captures the stones, but the capture is not big and the stones provide useful aji at A or B. I don't really know how to use WHite's sente either, but I don't think Black can match White' three corners and komi. Probably WHite just has to make shape in the centre to control the game.
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Re: How is your positional judgement?

Post by dfan »

Dusk Eagle wrote:But I would never assign a ~90% win rate to one side in these positions like Elf is so keen to.
To put "90%" in terms some of us are more comfortable with, KataGo estimates the score of the first position Bill posed (the only one I fed it) at around +5 for the side that's ahead, and puts the win rate in the 60s (as the other bots do).
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Re: How is your positional judgement?

Post by Knotwilg »

edited to include the answer to Joaz' fine inclusion of a probe

(don't know if Bill still likes it :) )
Last edited by Knotwilg on Thu Sep 12, 2019 9:00 am, edited 1 time in total.
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Re: How is your positional judgement?

Post by mhlepore »

dfan wrote:
Dusk Eagle wrote:But I would never assign a ~90% win rate to one side in these positions like Elf is so keen to.
To put "90%" in terms some of us are more comfortable with, KataGo estimates the score of the first position Bill posed (the only one I fed it) at around +5 for the side that's ahead, and puts the win rate in the 60s (as the other bots do).
Is it possible that there is a hardware issue at play? (For example, if the elf evaluation is on a machine without a GPU, but the others are using a GPU)

Otherwise it is headscratching to see strong bots vary that much.
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Re: How is your positional judgement?

Post by Kirby »

Elf usually has pretty high variation in winrates compared to other bots, so it’s not surprising to me that LZ is around 60 and Elf is around 90. I would be more surprised if Elf were around 70 and LZ were at 40, because that’d be a different interpretation of who had the lead.
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Re: How is your positional judgement?

Post by dfan »

mhlepore wrote:
dfan wrote: To put "90%" in terms some of us are more comfortable with, KataGo estimates the score of the first position Bill posed (the only one I fed it) at around +5 for the side that's ahead, and puts the win rate in the 60s (as the other bots do).
Is it possible that there is a hardware issue at play? (For example, if the elf evaluation is on a machine without a GPU, but the others are using a GPU)
The KataGo evaluation was with approximately the same number of playouts as the ELF evaluation.
Otherwise it is headscratching to see strong bots vary that much.
ELF is very, very opinionated. It is not unusual for it to give a position a 90% win rate while other strong bots give it a win rate more like 65%.
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Re: How is your positional judgement?

Post by Bill Spight »

dfan wrote:
mhlepore wrote:Otherwise it is headscratching to see strong bots vary that much.
ELF is very, very opinionated. It is not unusual for it to give a position a 90% win rate while other strong bots give it a win rate more like 65%.
Since, as players approach perfection, their winrate estimates will approach 100% or 0%, we might say that Elf is very, very self-confident. :cool: ;)
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