I played a long leisurely game today against someone from the local club -- almost 4 hours. I won playing white, but neither of us could figure out where black went wrong. I ran it through Lizzie to see if she could identify the issue, but she seems to think that white is at 60% by move 20. Was the pincer at C12 really a bad move? It seemed standard.

EDIT: Further review suggests that Lizzie thinks that black's prospects shift significantly between moves 49 and 55. I see how black's three moves are not ideal, but I'm honestly surprised that they are that decisive.

Even more strange is that Lizzie does not seem to like the standard jump and press joseki. (And I checked and it doesn't seem unique to this board position.) In this position, she strongly prefers A or B to the standard black reply. She thinks the result of the standard joseki is to give white close to a 60% winrate while either of these moves by black bring the winrate from the normal starting range to 50%. With A, she wants to push and cut. I let it play out for several thousand visits and the sequence had not settled down. She kept switching between various ugly fighting variations.

Click Here To Show Diagram Code

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

B lead to an interesting joseki-like sequence:

Click Here To Show Diagram Code

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

Click Here To Show Diagram Code

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

If someone with a fast GPU were inclined, I'd be interested to see what you get if you try to replicate this. I'm stuck with my CPU and so, I've hit the limit of what I think I can do.

Here is the winrate delta for white:


And here is the full game. Any thoughts would be appreciated!

The game move at E13 allows white to start a small fight that strengthens him. G14 or something similar looks to fight on a larger scale where black has more targets.

Click Here To Show Diagram Code

[go]$$c Position at move 69
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . X O . . |
$$ | . O O . . . . X . . X O . X . X O . . |
$$ | . O X X . X . . . X . O . . X O . . . |
$$ | . X X . . . . O . . . . . X . O . . . |
$$ | . . O . O . B . . . . O . . . . O . . |
$$ | . . . . C . . . . . . . . X . . . . . |
$$ | . . X X O . . . . . . . . . . . . . . |
$$ | . . X O . . . . . . . . . . . . O . . |
$$ | . . X O . . . . . , . . . . . , . . . |
$$ | . . . O . . . . . . . . . . X . X . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . X . . |
$$ | . X . . . . . X . . . . . . . . . . . |
$$ | . O X X . X . X O , . . . . . O . O . |
$$ | . O O O X . . O X O . . . O . . . . . |
$$ | . . . O O X . X X O . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

_________________
Help make L19 more organized. Make an index: https://lifein19x19.com/viewtopic.php?f=14&t=5207

AlphaGo does not seem to like pincers as much as humans do.



I seem to recall that humans began to prefer "a" or "b" to even before the AI era. By how much I am not sure.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.