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[go]$$Bcm27 Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . . . . , X . . |
$$ | . . X O O . . . . b . . . . . . X . . |
$$ | . . . X . . . . . . . . . . . d O . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . c . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , O . . |
$$ | . . . a O . X . . X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I find positions like these quite difficult to deal with. Black just has to make a good move, without an obvious weak group to target or reinforce. 'a' through 'd' all look plausible.

'a' looks like a good move, but I am concerned it is slow.

'b' just looks like pulling a single stone out, but I don't see the point. White has a base and 'd' to help. I'm worried about just making a target.

My preference is 'c'. It moves first into the largest open space and aims at the weaknesses in the large enclosure.

'd' is interesting, building strength for future activities, but I'm not strong enough to figure if that's better than 'c'.

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[go]$$Bcm27 Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . . . . , X . . |
$$ | . . X O O . . . . . . . . . . . X . . |
$$ | . . . X . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 7 . . . . . . . . . . . . . . . |
$$ | . . . 5 6 . 8 . . . . . . . . . . . . |
$$ | . . . X 4 . . . . . . . . . . . . . . |
$$ | . . . . O . 3 . . . . . . . . . 9 . . |
$$ | . . X , . . . . . , . . . . . , O . . |
$$ | . . . 1 O . X . . X . . . O . . . . . |
$$ | . . . . 2 . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

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[go]$$Bcm27 Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . 9 . . , X . . |
$$ | . . X O O . . . . . . . . . . . X . . |
$$ | . . . X . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . 3 5 7 . |
$$ | . . . . O . . . . . . . . . 6 2 1 4 . |
$$ | . . X , . . . . . , . . . . . , O 8 . |
$$ | . . . . O . X . . X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

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[go]$$Bcm27 Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . . . . , X . . |
$$ | . . X O O . . . . 1 . 2 . . . . X . . |
$$ | . . . X . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . 3 . 4 . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . 5 . . |
$$ | . . X , . . . . . , . . . . . , O . . |
$$ | . . . . O . X . . X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I'm stealing PWaldron's diagram because I think that it clearly defines the major places of interest.

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[go]$$Bcm27 Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . . . . , X . . |
$$ | . . X O O . . . . b . . . . . . X . . |
$$ | . . . X . . . . . . . . . . . d O . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . c . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , O . . |
$$ | . . . a O . X . . X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I differ, however in my evaluation of the four plays. All look good for black, but both 'b'and 'c' can go badly for black if white gets too much strength around 'd'.

Therefore, I'd play 'd' first, thereby having the strength to make 'c' and 'b' miai. And black still has 'a' for later if he comes out of a 'b; or 'c' fight with sente.

To those who would play the top right: consider the tewari

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[go]$$Bcm27 Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . . . . , X . . |
$$ | . . X O O . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . 1 . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , O . . |
$$ | . . . . O . X . . X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Sure, that move on its own is slow, but is it worse than this exchange for White which is what you need to compare it to for a valid tewari? One concrete downside of this exchange other than just losing points and making black stronger is white losses the standard continuation of attach and bulge with a-c as black can super easily play d now that White can't counter atari at 29.

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[go]$$Bcm27
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . d . . |
$$ | . . O O . O O . . X . O . . O . a b . |
$$ | . . X , . X . . . , . . . . . c X . . |
$$ | . . X O O . . . . . . . . . . . 3 . . |
$$ | . . . X . . . . . . . . . . . X 2 . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , O . . |
$$ | . . . . O . X . . X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Or an alternative tewari, black played the knight answer in response to the approach, very common move these days. Instead of locally normal move at a white attached at 1, black haned outside, for sure a bad exchange for white. Then white tenukid, and black fixed with 4. 4 is probably slow, but is it worse than 1 for 2?

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[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . . . . , X . . |
$$ | . . X O O . . . . . . . . . . . 4 . . |
$$ | . . . X . . . . . . . . . . . X 1 . . |
$$ | . . . . . . . . . . . . . . . . 2 . . |
$$ | . . . . . . . . . . . . . . . . a . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , O . . |
$$ | . . . . O . X . . X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I must say that John's musings about heuristics that take #stones/area into account, help me make decisions in unclear situations (or rather unclear vision on situations).

First of all, I'm ruling out the 1 space jump at the top. It's separating strong groups. There's no point to that.
The top right is confusing most of us. It's overconcentrated already but there's bad aji. How to reinforce effeciently? Probably by playing away from it but still affecting it.
The lower left gives an opportunity to make territory while attacking but there's a danger of losing sente.
The lower right is the area of growth for White. It's where most of my sequences aim for next.

John's heuristic also points to the lower right as an area for Black to move into.

Of all my sequences, I like this one best:

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[go]$$Bcm27 Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . 9 . . , X . . |
$$ | . . X O O . . . . . . . . . . . X . . |
$$ | . . . X . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . 3 5 7 . |
$$ | . . . . O . . . . . . . . . 6 2 1 4 . |
$$ | . . X , . . . . . , . . . . . , O 8 . |
$$ | . . . . O . X . . X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

It fulfills all requirements raised above and also keeps sente.

Is it better though than simply playing a 1 space check? Maybe 4 forcing stones is a little too heavy.

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[go]$$Bcm27 Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . . . . , X . . |
$$ | . . X O O . . . . . . . . . . . X . . |
$$ | . . . X . . . . . . . . . . . 2 O 3 . |
$$ | . . . . . 6 . . . . . . . . . 4 X . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . 1 . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , O . . |
$$ | . . . . O . X . . X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

seems to lose the initiative.

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[go]$$Bcm27 Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . . . . , X . . |
$$ | . . X O O . . . . . . . . . . . X . . |
$$ | . . . X . . . . . . . . . . . 2 O 3 . |
$$ | . . . . . 6 . . . . . . . . . 4 X . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . 6 1 . . |
$$ | . . X , . . . . . , . . . . . , O . . |
$$ | . . . . O . X . . X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Then again ...

White's is so severe that it's always sente and it's always leaving Black with problems he wouldn't have if he played there himself.

Still, I don't like a Black move there either. So I guess Black is simply behind, if he needs to play a bad move.

You like that outside attachment of the big shimari. Are you aware that's generally considered a bad move, both pre- and post-AI (because White simple nobi is efficient answer, unlike with small shimari), but think this position is an exception, or you just didn't know that or got confused with the low shimari and like attachments more now?

The AI attachments against the big shimari are, most common q4, and sometimes p4. Though I don't like either of them much here as I don't want to make the white corner stronger given black m3 might be a good move to defend that lower side group in the future and then I'd want to have kept the option for shenanigans inside with q3.

I was looking for a way to keep sente. A simple check doesn't do that. The attachment may be inspired by seeing it against the small shimari. You're undoubtably right it is not a good choice against a big shimari.

By showing the sequences I'm seeing, I'm also showing are sequences I'm not seeing.

The game is GoGoD 1620-00-00at, Nakamura Doseki (W) vs. Yasui Santetsu.

How we got here.

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[go]$$Bcm5 Blunder
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . 1 . 4 . . O . . . . |
$$ | . . . , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . 3 . . |
$$ | . . . . . . . . . . . . . . . . 2 . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . a . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Elf considers to be a mistake and to be a blunder. Better to occupy the last open corner at a. With mistakes on both sides we later reach the problem position where Black would be significantly behind if giving komi. Even with no komi, Black is maybe a few points behind, I suppose.

Click Here To Show Diagram Code

[go]$$Bcm27 Game record, jump-jump
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . . . . , X . . |
$$ | . . X O O . . . . 1 . 2 . . . . X . . |
$$ | . . . X . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , O . . |
$$ | . . . . O . X . . X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

The one space jump is never bad, they say. Well, Elf does not like and reckons that it loses 13½% to par. It doesn't much like , either, which loses 11% to par.

Here is Elf's mainline variation for White's reply.

Click Here To Show Diagram Code

[go]$$Wcm28 Mainline for
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . . . . , X . . |
$$ | . . X O O . . . . X . . . . . . X . . |
$$ | . . . X . . . . . . . . . . . 1 O 2 . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X a . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . X , . . . 5 3 , . . . . . , O . . |
$$ | . . . . O . X . 4 X . 6 . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

takes kikashi. a and 30 are also playable. and push down on Black on the bottom side. reaches out for lebensraum and to threaten the White corner.

Click Here To Show Diagram Code

[go]$$Wcm34 Mainline for , continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . . . . , X . . |
$$ | . . X O O . . . . X . . . . . . X . . |
$$ | . . . X . . . . . . . . . . . O O X . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . 6 . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . X , . 3 1 O O , . . . . . , O . . |
$$ | . . . 5 O 2 X . X X . X . O . . . . . |
$$ | . . . . 4 . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

and continue to press down, building a wall. prevents a White descent here with sente. Then plays the double keima in the bottom left, extending Black's moyo into the center.

Top choice: Honte, shared blind spot

Click Here To Show Diagram Code

[go]$$Bcm27 Honte, thickness
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . . . . , X . . |
$$ | . . X O O . . . . . . . . . . . X . . |
$$ | . . . X . . . . . . . . . . . 1 O . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , O . . |
$$ | . . . . O . X . . X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

is a thick honte in the top right, preventing the White kikashi. It has been, and will continue to be, a blind spot for both players. Elf wanted White to take the kikashi immediately after , and has wanted White to do so for all but two moves since then. It has wanted Black to play the honte at move 13, and at all but three moves since then. Black finally played there with .

Click Here To Show Diagram Code

[go]$$Bcm27 Mainline for
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . . . . , X . . |
$$ | . . X O O . . . . . . . . . . . X . . |
$$ | . . . X 5 . . . . . . . . . . 1 O . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . X , . . 4 . 2 , . . . . . , O . . |
$$ | . . . . O . X . 3 X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

As people have pointed out, the top side per se is not urgent. switches to the bottom side, and bolsters the top edge of Black's left side moyo.

Click Here To Show Diagram Code

[go]$$Wcm32 Mainline for , continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . . . . , X . . |
$$ | . . X O O . . . . . . . . . . . X . . |
$$ | . . . X X . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , 9 . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 8 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . X , . 3 O 1 O , . . . . . , O . . |
$$ | . . 7 5 O 2 X . X X . 6 . O . . . . . |
$$ | . . . . 4 . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

continues play on the bottom side, much as in the above variation. After extends towards the bottom right corner, pushes into the bottom left corner, threatening the nearby Black stones, which Black protects with a 4th line extension. Then reduces the Black left side.

I mainly chose this play because Elf preferred a thick play in the opening, when bots usually prefer light play. Given the human blind spot, I suppose that other bots will prefer it, as well.

I think I would have missed it, too. The White kikashi seems equitable, and preventing it at the risk of overconcentration doesn't look as big to me at this point as the block at E-06 or P-05 against the bottom right corner. But Elf has considered the Q-14 point to be urgent for quite a while.

Hum, ok. This one, then:

Click Here To Show Diagram Code

[go]$$Bcm27 Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . O O . . X . O . . O . . . . |
$$ | . . X , . X . . . , . . . . . , X . . |
$$ | . . X O O . . . . . . . . . . . 1 . . |
$$ | . . . X . . . . . . . . . . . 3 2 . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , O . . |
$$ | . . . . O . X . . X . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

1 is very nearly a pass. 2 for 3 is bad but loses only the attachment to the isolate stone, which isn't much.

edit: just saw the solution. i am doing very badly at these.. i suppose that means my evaluation is close with bill's.
i did notice that the temperature on this board is low, but still undervalued the difference between both players' moves in the top right. i would have played something against the bottom right corner.

Speculatively:
Current position:
1. There are many small fights on the board. The upper right looks a bit bizarre. K17 is well behind enemy lines, but there is no eyespace or counterattack potential. So although K15 seems like a move, Q14 seems much more attractive locally.
2. Otherwise, the lower left W group isn't alive and can be attacked naturally by D3. Perhaps E6 is also possible but it seems W can lean at G4 naturally and then F6.
3. B can expand the left but there are some weaknesses and the upper W side is hotter as K17 is weak. Later M3, R6 will be big.

Opp to play
1. Q14, D12 look natural.

Past:
1. B's shapes seem less efficient, especially the upper right, and K17. The lower left is worse for W but I think it is mitigated by W's centre strength from the moyo.

Check:
1. basically correct. Looking at other people's misunderstanding of the lower right, it seems people seem too happy to lean on the weakness from the right side which gives W more space on the centre, corner and lower side. That's locally bad shape, helping W by playing forcing moves close to a weakness but no close enough to even gain profit from it (which requires the 4-4 attachment). It's not worth it, when there was plenty of aji to live in the corner, which is natural when B is alive on both sides.