Life In 19x19

I know the typical joseki is like this

Click Here To Show Diagram Code

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

But I've seen some players go like this

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

I'm curious firstly, is there a big difference when black goes E16 as opposed to E17. Second is, how does black follow up when white responds like this

Click Here To Show Diagram Code

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

My initial thought was this

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

To be honest, whites move at F16 looks really dumb but I ask because I've seen so many people do that. I thought I probably missed something.

I think white shouldn't cut at 4 and continue the "joseki" as usual (Playing a hane on the second line), being happy that black gave him extra profit. I'd rather have the thickness, but that's just me.

More common is this:

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[go]$$Bc tenuki
$$ ------------------
$$ | . . . . . . . . .
$$ | . . . . . 2 . . .
$$ | . . O O . . . . .
$$ | . . X X 1 . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

The reason for this joseki is so that black can get sente because in the usual 3-3 invasion white ends in sente. Black surrenders more and leaves white more open on the top but, in exchange, gets to tenuki.

My thoughts:

The cut seems like an overplay to me, unless white is strong on the right or has the ladder.

Click Here To Show Diagram Code

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

There's no need to play here, since threatens the group of three, not . Now, white's in trouble.

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

Now white has to push through and cut in order to live:

Click Here To Show Diagram Code

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

And the result doesn't seem good for white.

Instead, white could play like this:

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

This doesn't seem bad for white, but I think is a mistake if black has the ladder. In that case, I think black should instead do:

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[go]$$Bc With the ladder in favor of black:
$$ ------------------
$$ | . 9 . c . 8 . . .
$$ | 0 4 a b . 6 7 . .
$$ | . 3 O O O X 1 . .
$$ | . 5 X X X O . . .
$$ | . . . . . 2 . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

Click Here To Show Diagram Code

[go]$$Bc Another variation
$$ ------------------
$$ | . . . 0 . 9 . . .
$$ | 8 O . . . 6 7 . .
$$ | . X O O O X 1 . .
$$ | . X X X X O . . .
$$ | . . . . . 2 . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

Maybe it goes like below if the ladder doesn't favor black?

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

This diagram doesn't look bad for white. Maybe black would prefer to descend to the second line for his first move if he doesn't have the ladder.

There's a lot of diagrams here for a complicated position, so I've probably made some mistakes.

Dusk Eagle wrote:

$$Bc Another variation
$$ ------------------
$$ | . . . 0 . 9 . . .
$$ | 8 O . . . 6 7 . .
$$ | . X O O O X 1 . .
$$ | . X X X X O . . .
$$ | . . . . . 2 . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .

Click Here To Show Diagram Code

[go]$$Bc Another variation
$$ ------------------
$$ | . . . 0 . 9 . . .
$$ | 8 O . . . 6 7 . .
$$ | . X O O O X 1 . .
$$ | . X X X X O . . .
$$ | . . . . . 2 . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

<snip>

so I've probably made some mistakes.

Indeed, black 9 at 10 kills.

I should clarify that white's cut is just what I happen to come across. People for some reason love to play that cut. I always suspected that it was a bad move.

I saw this extension rather than hane in a pro game today (move 91):

http://www.go4go.net/go/games/sgfview/42133

The idea is black wants sente to kill off the lower side group. White pushes rather than slides so that when black does tenuki his follow up hane is more severe.