Opening problems for AI: Problem 43

Bill Spight · #1

Only move problem.

White to play.

Click Here To Show Diagram Code: [go]$$Wcm18 Where is White's only move? $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . X X . . . . . . . . . . . . . . . . | $$ | X . X O . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | . O X O . . . . . . . . . . . . . . . | $$ | . X X , . . . . . , . . . . . , . . . | $$ | . . O . O . X . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Enjoy!

Uberdude · #2

Knotwilg · #3

Two possibilities:

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

The question is: is :w3:

necessary?

Click Here To Show Diagram Code: [go]$$Wc Where is White's only move? $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . X X . . . . . . . . . . . . . . . . | $$ | X . X O . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | . O X O . 6 . . . . . . . . . . . . . | $$ | . X X 1 . . . . . , . . . . . , . . . | $$ | . 2 O 5 O . X . . . . . . . . . . . . | $$ | . . 4 . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

If White plays :w3:

elsewhere then the group becomes a floating one. If :w5:

at

or ko, it's not much better.

Click Here To Show Diagram Code: [go]$$Wc Where is White's only move? $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . X X . . . . . . . . . . . . . . . . | $$ | X . X O . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | . O X O . . . . . . . . . . . . . . . | $$ | . X X 2 3 . . . . , . . . . . , . . . | $$ | . 1 O . O . X . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

This is more clearly gote for White.
The result is territorially better than the gote variation above.
I read that Uberdude finds White's shape ruined.
I'm not sure which is better.

Click Here To Show Diagram Code: [go]$$Bc Follow up $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . X X . . . . . . . . . . . . . . . . | $$ | X . X O . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | 3 O X O 1 4 . . . . . . . . . . . . . | $$ | . X X X O . . . . , . . . . . , . . . | $$ | . O O 2 O . X . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Right after this, there's ladder aji. White may decide to sacrifice the 4 stones. The first variation doesn't have this aji.

Joaz Banbeck · #4

This seems to preserve white's eye space as well as any move.

Click Here To Show Diagram Code: [go]$$Wcm18 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . X X . . . . . . . . . . . . . . . . | $$ | X . X O . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | . O X O . . . . . . . . . . . . . . . | $$ | . X X , . . . . . , . . . . . , . . . | $$ | . . O . O . X . . . . . . . . . . . . | $$ | . . W . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Kirby · #5

I'd just play here:

or maybe here:

Harleqin · #6

Joaz Banbeck · #7

I'm highly skeptical of tenukiing to a corner. With Bill's #42 still in mind, I'm seeing honte moves in my sleep.

But I don't like playing the corner either. My gut says that a five point move in gote close to black's strength can't be best.

Perhaps there is a possibility in between.

Click Here To Show Diagram Code: [go]$$Wcm18 A compromise: not corner, but not tenuki. $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . X X . . . . . . . . . . . . . . . . | $$ | X . X O . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | . O X O . . . . . . . . . . . . . . . | $$ | . X X , . . . W . , . . . . . , . . . | $$ | . . O . O . X . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Uberdude · #8

Joaz Banbeck wrote:

This seems to preserve white's eye space as well as any move.

Click Here To Show Diagram Code: [go]$$Wcm18 $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . X X . . . . . . . . . . . . . . . . | $$ | X . X O . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | . O X O . . . . . . . . . . . . . . . | $$ | . X X , . . . . . , . . . . . , . . . | $$ | . . O . O . X . . . . . . . . . . . . | $$ | . . W . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Not as well as this move, which I can only see advantages and no disadvantages over your move, except perhaps making the opponent lose concentration from the shock of such a bizarre move! How can you go from so right on the last problem to so wrong here?!

Click Here To Show Diagram Code: [go]$$Wcm18 $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . X X . . . . . . . . . . . . . . . . | $$ | X . X O . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | . O X O . . . . . . . . . . . . . . . | $$ | . X X , . . . . . , . . . . . , . . . | $$ | . W O . O . X . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

ez4u · #9

Bill Spight wrote:

Only move problem.

White to play...
Enjoy!

Huh? But you said... :scratch:

Bill Spight wrote:

"Tenuki is always an option!"

Bill Spight · **#10**

ez4u wrote:

Bill Spight wrote:

Only move problem.

White to play...
Enjoy!

Huh? But you said... :scratch:

Bill Spight wrote:

"Tenuki is always an option!"

Gomoto · **#11**

A hideous insidious riddle it is

I thought about B3

(mild) spoiler

Bill Spight · **#12**

yoyoma · **#13**

Click Here To Show Diagram Code: [go]$$Wcm18 katago evals: $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . a . . . . . , . . . . . c . . . | $$ | . . . . . . . . . . . . . . . d . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . X X . . . . . . . . . . . . . . . . | $$ | X . X O . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | . O X O . . . . . . . . . . . . . . . | $$ | . X X b . . . f . , . . . . . , . . . | $$ | . e O . O . X . . . . . . . . . . . . | $$ | . . g . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Code:

a - 4-4 upper left  : White 49.5%  -0.1pts  (Kata's choice)
b - solid connect   : White 47.1%  -0.2pts  (Elf's "only move")
c - 4-4 upper right : White 46.8%  -0.2pts
d - 5-4 upper right : White 41.5%  -0.9pts  (Game move)
e - shoulder hit    : White 43.6%  -0.7pts
f - block corner    : White 36.1%  -1.7pts
g - descend         : White  4.3% -10.2pts

Kata is not so insistent about connecting. It's a good move, but so is taking the corners. If White takes a corner, Kata also thinks Black can choose taking a corner or playing the forcing push.

Bill Spight · **#14**

yoyoma wrote:

Click Here To Show Diagram Code: [go]$$Wcm18 katago evals: $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . a . . . . . , . . . . . c . . . | $$ | . . . . . . . . . . . . . . . d . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . X X . . . . . . . . . . . . . . . . | $$ | X . X O . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | . O X O . . . . . . . . . . . . . . . | $$ | . X X b . . . f . , . . . . . , . . . | $$ | . e O . O . X . . . . . . . . . . . . | $$ | . . g . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Code:

a - 4-4 upper left  : White 49.5%  -0.1pts  (Kata's choice)
b - solid connect   : White 47.1%  -0.2pts  (Elf's "only move")
c - 4-4 upper right : White 46.8%  -0.2pts
d - 5-4 upper right : White 41.5%  -0.9pts  (Game move)
e - shoulder hit    : White 43.6%  -0.7pts
f - block corner    : White 36.1%  -1.7pts
g - descend         : White  4.3% -10.2pts

Kata is not so insistent about connecting. It's a good move, but so is taking the corners. If White takes a corner, Kata also thinks Black can choose taking a corner or playing the forcing push.

This is great!

Elf apparently developed a blind spot that kept it from exploring alternatives. It is extremely rare for it to like a play so much that it gives it over 100k rollouts.

How many rollouts does KataGo give these different options?

Uberdude · **#15**

I've seen Elf (v2 I think) have a blindspot and some % winrate change when shown the shockingly unusual move 3 of a 3-4 point instead of a 4-4. Other bots are less blinkered and more reliable for analysis IMO.

Bill Spight · **#16**

Uberdude wrote:

I've seen Elf (v2 I think) have a blindspot and some % winrate change when shown the shockingly unusual move 3 of a 3-4 point instead of a 4-4. Other bots are less blinkered and more reliable for analysis IMO.

Well, the bots are at present good tools to assist a human analyst, but I would not rely upon any computer program alone for analysis. They are not trained to be analysts. Now, lightvector has used human games in training KataGo to make it better for analysis, but the main impetus for bot development is to increase its overall playing strength. The same seems to be true for chess engines, some 25 years or so since the first superhuman engines appeared. Chess engines still have well known blind spots.

Ordinarily I would not be surprised that KataGo or any other bot would prefer a different play than Elf. From what little information I have, a concordance rate between bots of around 80% is not unexpected. I do expect bots to agree about sufficiently bad human errors, which is the case here. KataGo figures a winrate loss for Sansa's play at 8%, about half the loss that Elf figures, but that's in line with how differently they estimate winrates. I am however surprised that, having spent at least 143.8k rollouts on this position, Elf did not pick up KataGo's top choice and give it at least 1500 rollouts.

ez4u · **#17**

Bill Spight wrote:

yoyoma wrote:

Click Here To Show Diagram Code: [go]$$Wcm18 katago evals: $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . a . . . . . , . . . . . c . . . | $$ | . . . . . . . . . . . . . . . d . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . X X . . . . . . . . . . . . . . . . | $$ | X . X O . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | . O X O . . . . . . . . . . . . . . . | $$ | . X X b . . . f . , . . . . . , . . . | $$ | . e O . O . X . . . . . . . . . . . . | $$ | . . g . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Code:

a - 4-4 upper left  : White 49.5%  -0.1pts  (Kata's choice)
b - solid connect   : White 47.1%  -0.2pts  (Elf's "only move")
c - 4-4 upper right : White 46.8%  -0.2pts
d - 5-4 upper right : White 41.5%  -0.9pts  (Game move)
e - shoulder hit    : White 43.6%  -0.7pts
f - block corner    : White 36.1%  -1.7pts
g - descend         : White  4.3% -10.2pts

Kata is not so insistent about connecting. It's a good move, but so is taking the corners. If White takes a corner, Kata also thinks Black can choose taking a corner or playing the forcing push.

This is great!

Elf apparently developed a blind spot that kept it from exploring alternatives. It is extremely rare for it to like a play so much that it gives it over 100k rollouts.

How many rollouts does KataGo give these different options?

First, here is katago's policy. Elf's preferred play is high but not as high as the upper left.

Of course the PO's depend on how long we search.

But after 2.8 million... (note my komi was set to 6.5 points and therefore the winrates are quite different)

Bill Spight · **#18**

ez4u wrote:

First, here is katago's policy. Elf's preferred play is high but not as high as the upper left.

Of course the PO's depend on how long we search.

But after 2.8 million... (note my komi was set to 6.5 points and therefore the winrates are quite different)

This is great, Dave! Many thanks. :salute:

Two comments. First, with only 521 playouts, KataGo's evaluation of Sansa's 5-4 move in the top right has a large margin of error. Elf does better in this regard, by inheriting the evaluation from its best reply to that move. I expect that yoyoma does even better, by making the play itself to get its evaluation with several thousand rollouts.

Second, even though I have no experience with KataGo, I think that the 3% winrate difference between KataGo's choice and Elf's, with 1.6M and 147K rollouts, respectively, puts Elf's choice in the doubtful category.

The fact that Elf concentrates on one play to the virtual exclusion of others indicates that it likes that play. However, that does not mean that other bots will like it much. Therefore, this will be the last "only move" problem.

Gomoto · **#19**

Quote:

Therefore, this will be the last "only move" problem.

The only move now ;-)

dhu163 · **#20**

Opening problems for AI: Problem 43

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