I am currently investigating the following three moves:

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[go]$$Wcm10
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . b c . . . . . . . . . . . . . . . |
$$ | . . . , . O . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . a . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . . . . . . . . . . . . . |
$$ | . X X , . . . . . , . . . . . , . . . |
$$ | . . . . X . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I looked at a lot of options for White. Many of them seem playable. Let's look at some of them.

1). A play in the corner

There are four ways one could play in the corner:

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[go]$$Wc
$$ ---------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . a b . . . . . .
$$ | . . c d . O . . . ,
$$ | . . . . . . . . . .
$$ | . . . X . . . . . .
$$ | . . . . . . . . . .[/go]

For example,

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[go]$$Wc
$$ ---------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . 1 . . . . S . .
$$ | . . . , . O . . . ,
$$ | . . . . . . . . . .
$$ | . . . X . . . . . .
$$ | . . . . . . . . . .
$$ | . . M M . . . . . .
$$ | . . . . . . . . . .
$$ | . . 2 , . . . . . ,
$$ | . . . . . . . . . .
$$ | . . . . . . O . . X
$$ | . . S . . . . . . .
$$ | . . . . . . . . . .
$$ | . . O O . . . . . .
$$ | . X X , . . . . . ,
$$ | . . . . X . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ ---------------------[/go]

Next, White would aim to exploit the weaknesses marked . What worried me about this, however, is that Black can aim to exploit the weaknesses marked .

2). One-space extension from the stone at the top

This move could lead to the following continuation:

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[go]$$Wc
$$ ---------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . 4 . . . . . . .
$$ | . . . , . O . . . ,
$$ | . . . . . . . . . .
$$ | . . . X . 1 . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . 2 . . . . . . .
$$ | . . . , . . . . . ,
$$ | . . 3 . . . . . . .
$$ | . . . . . . O . . X
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . 5 O O . . . . . .
$$ | . X X , . 6 . . . ,
$$ | . . . . X . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ ---------------------[/go]

Here, both Black and White groups on the left side would become stable. However, Black's territorial gains would be greater. In exchange, White would have influence on the top side. Yet, it could prove difficult to sufficiently monetize this influence so as to offset the territorial loss on the left.

3). Pincer

I primarily considered these pincers:

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[go]$$Bc
$$ ---------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . , . O . . . ,
$$ | . . . . . . . . . .
$$ | . . . X . . . . . .
$$ | . . . . . . . . . .
$$ | . . a b c . . . . .
$$ | . . d e . . . . . .
$$ | . . f g . . . . . ,
$$ | . . . . . . . . . .
$$ | . . . . . . O . . X
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . O O . . . . . .
$$ | . X X , . . . . . ,
$$ | . . . . X . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ ---------------------[/go]

All these pincers seem interesting to me. For example, "f" is one of the joseki-recommended extensions from the two stones on the bottom. However, since I would like to fight in this game, I decided to play a close pincer so as to apply maximum pressure onto the Black stone. Of these, "b" seemed to me like the best way to both deny Black a stable position in the corner and to help White in the running battle, which is likely to arise.

topazg now faces an interesting (and difficult) choice. Does he run at "a" (which I think he will) or does he play in the corner (most likely at the 4-4 point) ... or does he go for something crazy like "c"?

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

As discussed. I think White is being a bit generous to Black here. Everything is settling, and I'm actually picking up points. His is very high, and combined with B4 White doesn't really have any easy large points on the left. Now White has effectively approached my 4-4 high, and after I extended, has pincered. I'd have been very happy with the move order below:

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[go]$$Bcm9
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 1 . 2 . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 3 . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 4 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . . . . . . . . . . . . . |
$$ | . X X , . . . . . , . . . . . , . . . |
$$ | . . . . X . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

So, I'm happy here too. I think White should have taken the top left and forced me to settle on the left.

Agree with topazg, W should have taken corner as that is key place to make a base. Playing for centre rarely works if your opponents groups are strong and you directly try to enclose points (you just won't have enough), best way to play for centre is to attack weak groups but white let black make a strong group here.

topazg did play at 4-4, after all. Interesting. Before anything else, I'll think about this move:

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

The following looks very promising:

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

I think Black has to connect, after which I can jump out to F13, more or less linking my stones and, more importantly, containing Black in the corner.

feels like a big thank-you move.

No complaints about that. Feels a bit of an unnecessary peep to be honest, especially as it removes so much of my C15 / C17 aji. White's creating a fairly thin position everywhere at the moment. This is the second corner where I've gained good points, although I sort of owe another move on the bottom left as being pressed down is a bit disappointing. The aji White has left on the left is painful too ... for example:

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[go]$$Wcm14
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . 6 4 5 . . . . . . . . . . . . |
$$ | . . . X . O 7 . . , . . . . . , . . . |
$$ | . . . 2 1 . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . X . . . |
$$ | . . . . . 3 . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . a , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . 8 . c . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . b O O . . . . . . . . . . . . . . . |
$$ | . X X , . . . . . , . . . . . , . . . |
$$ | . . . . X . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Making miai of "a" and "b" (and even running out at "c" is painful for White), White is just failing to make enough anywhere. It's big enough to play straight away ... I'm rather tempted to play an extension on the top or a top right corner move (or play that move I owe in the bottom left) instead of something like this though - point is, White's going to want to fix it at some point later as a somewhat slow gote move.

This result seems quite good for me. Essentially, this kind of a result is the reason why I thought topazg would jump out instead of taking the 4-4 point.

Next, topazg may consider playing a forcing move, which threatens to cut White in two:

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[go]$$Bc
$$ ---------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . X . O . . . ,
$$ | . . . X O . 1 . . .
$$ | . . . X . . . . . .
$$ | . . . . . O . . . .
$$ | . . . O . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .[/go]

Some thoughts:

The right side seems slightly unimportant because of the lower right 3-3, and I'm suspicious that my K8 stone will now act more as a "white can't make a big moyo" stone - I don't need to worry about making my own moyo as much as I'd thought as White's rather generously given me the lion's share of the points so far. The lower side also seems relatively uninteresting, as I'd need to fix the lower left shape, approach the lower right corner and make a lower extension to gain any really solid profit from that area.

The left side isn't as White as White would want because of the aji left in the last post, and that leaves the top side.

Because White has started to build that first piece of what could be provisionally thought of as thickness facing across the top side, now seems a valuable time to make an extension of my own along the top. I've chosen high because I think that works best with the top right and central stones, and I've chosen the position I have because I can happily extend in either way. Either of the following continuations seem good to me:

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[go]$$Wcm16
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . O . . 5 . 2 . . 3 . 4 . . . |
$$ | . . . X O . . . . . . . . . . . . . . |
$$ | . . . X . . . . 8 . 6 . . 7 . X . . . |
$$ | . . . . . 1 . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . . . . . . . . . . . . . |
$$ | . X X , . . . . . , . . . . . , . . . |
$$ | . . . . X . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Click Here To Show Diagram Code

[go]$$Wcm16
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 6 . . |
$$ | . . . X . O . . 3 , 2 . . 4 . 5 . . . |
$$ | . . . X O . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . X . . . |
$$ | . . . . . 1 . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . . . . . . . . . . . . . |
$$ | . X X , . . . . . , . . . . . , . . . |
$$ | . . . . X . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

So yeah, I'm already feeling good about this game now, which is nice within 20 moves.

I'll need to analyze the corner situation a bit more, but maybe I can do something like this:

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[go]$$Wc
$$ ---------------------
$$ | . . . . . . . . . .
$$ | . . 4 . 3 . . . . .
$$ | . . . . . . . . . .
$$ | . . . X . O . . . ,
$$ | . . . X O . . . . .
$$ | . 2 . X . . . . . .
$$ | . . . . . O . . . .
$$ | . 1 . O . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .[/go]

If all these white moves are sente, then Black would get shut in much tighter. Afterward, I could consider protecting my moyo on the left.

Obviously black won't respond as intrepid envisions. For example:

Click Here To Show Diagram Code

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

Edit: That being said, I'm a bit uncertain if black should even respond because the sequence above makes black's last move feel a bit too close to the wall. Perhaps black can also just consider tenuki as I don't see the corner dying.

I've been analyzing various ways of threatening Black's top-left corner from the outside so as to gain thickness in sente. However, what exactly is topazg's plan in case of an immediate 3-3 invasion? Either I am missing something or he is because, it seems to me, the 3-3 invasion lives unconditionally, forcing the Black group to run--and that's not easy to do because of the White stones on the outside. I need to study this more thoroughly.

Never mind, I spoke too soon. The marked stone makes a big difference--Black can play which otherwise would have been unreasonable.

Click Here To Show Diagram Code

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

White invasion fails.

Without the marked stone, this would happen following the moves above:

Click Here To Show Diagram Code

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

However, instead of trying to live unconditionally, can White play for a ko instead?

Click Here To Show Diagram Code

[go]$$Wc
$$ -----------------------
$$ | . . b a . . . . . . .
$$ | . 5 . 3 4 . . . . . .
$$ | . . 1 2 . . . . . . .
$$ | . c . X . O . . . , X
$$ | . . . X O . . . . . .
$$ | . . . X . . . . . . .
$$ | . . . . . O . . . . .
$$ | . . . O . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .[/go]

Next, White responds with "b" to Black's "a," although Black might be able to play at "c" instead. In any case, even if a ko fight were to happen, the fight seems unwinnable for White at the present moment. White has one serious ko threat against the bottom-left corner, but not much beyond that. Black, meanwhile, has a few local ko threats and he is the first one to take the ko.

In other words, it's back to plan "A," which is to threaten the corner from the outside so as to obtain thickness in sente. Currently, I am trying to decide between these two moves:

Click Here To Show Diagram Code

[go]$$Wc
$$ -----------------------
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . X . O . . . , X
$$ | . . . X O . . . . . .
$$ | . . . X . . . . . . .
$$ | . a b . . O . . . . .
$$ | . . . O . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .[/go]

Possible sequences (among many others):

Click Here To Show Diagram Code

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

Here, is sente because of the threat of "a" while is sente because of "b."

Click Here To Show Diagram Code

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

It should be fun watching how topazg defends here. The task is not trivial.

Ok, time to settle with a reasonably big corner. Assuming he responds, I'm aiming at this:

Click Here To Show Diagram Code

[go]$$Wcm18
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . 4 2 3 . . . . . . . . . . . . |
$$ | . . . X . O a 5 . , X . . . . , . . . |
$$ | . . . X O . . . . . . . . . . . . . . |
$$ | . 6 . X . . . . . . . . . . . X . . . |
$$ | . . 1 . . O . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . . . . . . . . . . . . . |
$$ | . X X , . . . . . , . . . . . , . . . |
$$ | . . . . X . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

If he doesn't play to protect, I'm obviously going to go and cut.

topazg's move seems reasonable--and I am not unhappy to see it. I'll need to study its consequences some more. In the meantime, is a big move which protects the moyo on the left while threatening the corner as shown below. At the end of the sequence, Black still needs to defend against "a."

Click Here To Show Diagram Code

[go]$$Wc
$$ | . . . . . . . .
$$ | . . . . . . . .
$$ | . O O O . . . .
$$ | . X X 2 3 7 . .
$$ | . . . 1 X 5 . .
$$ | . a . 4 6 . . .
$$ | . . . . . . . .
$$ -----------------[/go]

Tenuki? Really? Well, I'll happily take my cash here...

In retrospect, maybe I should have thought about my move a bit before making it. Hopefully I did not lose an opportunity to kill the corner. Anyhow, topazg will now suffer some damage in the bottom left in return.

Click Here To Show Diagram Code

[go]$$B
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . O O O . . . . . . . . . . . . . . . |
$$ | . X X 1 2 . . . . , . . . . . , . . . |
$$ | . . . W X . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]

It's a logical followup to his last move, but I don't think it's as big as what I managed to pick up at the top.