How is your positional judgement? Game 26

Bill Spight · #1

Game 26

After :b33:

the Elf commentaries give one player an 89½% winrate estimate with 37.7k playouts. Which player is it?

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

Enjoy!

jlt · #2

Joaz Banbeck · #3

bayu · #4

Knotwilg · #5

xela · #6

xela · #7

And after looking at the other responses and checking with KataGo (warning: contains spoilers) --

Click Here To Show Diagram Code: [go]$$Wc $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O X . . . . . . . O . . . . . | $$ | . . . O . O . . . , . . . . . X . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . X O O X X X . . . . . . . . . . . | $$ | . . . X X O O . . . . . . . . . . . . | $$ | . . . . . X O . . . . . . . . . . . . | $$ | . . . . . X O . . . . . . . . . . . . | $$ | . . . , . X O . . , . . . . . , . . . | $$ | . . . . . X O . . . . . . . . . X . . | $$ | . . . 2 X O . . . . . . . . . . . . . | $$ | . . . 3 1 . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . O . . . . O X . . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Everyone else is assuming black can't get away with :b2:

at

. But why not? I can't actually see a sequence that's devastating for white.

Click Here To Show Diagram Code: [go]$$Wc $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O X . . . . . . . O . . . . . | $$ | . . . O . O . . . , . . . . . X . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . X O O X X X . . . . . . . . . . . | $$ | . . 9 X X O O . . . . . . . . . . . . | $$ | . . . 0 5 X O . . . . . . . . . . . . | $$ | . . . . . X O . . . . . . . . . . . . | $$ | . . . 8 6 X O . . , . . . . . , . . . | $$ | . . . 7 3 X O . . . . . . . . . X . . | $$ | . . . 4 X O . . . . . . . . . . . . . | $$ | . . . 2 1 . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . O . . . . O X . . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Here,

and

are captured. White can rip off the two stones above :w9:

, but is this really any worse than being submissive as in the first diagram? KataGo says yes, but only just under two points worse in a position where white is already more than ten points down. (If :w3:

at

, black is slightly better off.) So maybe it's worth black trying the more complicated line?

emerus · #8

dhu163 · #9

Hmm. Seems trickier.

B's shape on the left isn't pretty and the 3 cutting stones don't seem to be doing well. P4 is weird, surely helpful for B. However, given the rest of the board, I have to prefer W. Even though W needs to attack severely to convert the centre value.

For now, the upper left has miai of C16 and G17. In fact, B G17 is met by G16.

W's central double hane of E7 will close to seal the position or at least leave very bad aji inside. If all goes according to plan, W helps secure the lower left corner, restricting B to around 32pts locally. W can take sente for G17 on the upper side, for mutual eyespace. W's outside is a wall of length 10 with a cutting point but supported with lots of potential around and a very weak group at the top. On the rest of the board, W and B have an equal number of stones. So B has perhaps 10pts more territory by this estimate and sente. But I like the look of W here. I can't really explain it though. I think the point is that B hasn't yet made the right territory nor gotten potential to live in the heart of W's area. Even if B adds a move to defend their own area, W has time to defend themselves. It is difficult to see how B will make the value of territory when W is so thick.

Of course, I may be wrong because B can then play O16 next to naturally get into the upper side.

How is your positional judgement? Game 26

Who is online