Professionals have been playing 3-3 invasion very early in games recently. A lot of interesting outcomes.

http://www.go4go.net/go/games/sgfview/33944
http://www.go4go.net/go/games/sgfview/33959
http://www.go4go.net/go/games/sgfview/33961
http://www.go4go.net/go/games/sgfview/33973
http://www.go4go.net/go/games/sgfview/33975
http://www.go4go.net/go/games/sgfview/33981
http://www.go4go.net/go/games/sgfview/33990

That's seven examples in the most recent 50 games collected by Go4Go! Interestingly they often leave half-dead corners unattended for a long time, using the aji to try to gain from outside.

[Edit] Found a few more example. Seems Chinese pros like to play this way particularly.

http://www.go4go.net/go/games/sgfview/33933
http://www.go4go.net/go/games/sgfview/33936
http://www.go4go.net/go/games/sgfview/33895

yep very interesting. in 2 weeks i will be in korea , i will ask to my pro friend and probably post something if people want.

Please do come back and post. Beginners in the past were often told not to do such invasion too early. But seems pros are experimenting something new now.

Also S14 in these two games:

http://www.go4go.net/go/games/sgfview/33984
http://www.go4go.net/go/games/sgfview/33987

I don't recall pros doing those so early in games either.

A few of those games had this sequence:

Click Here To Show Diagram Code

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

In which case they would be experimenting with something old. This was a very popular pattern in the 90's (practically THE joseki in '95). Since it's a full joseki, I wouldn't qualify it as a 3-3 invasion.

Click Here To Show Diagram Code

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

This one, though, is very strange indeed. Are pros tired of keeping the invasion aji for later? Did they all attend a 'Play like Cho Chikun' seminar? Who knows!

Please do report back, lichigo. I think we're all going to be just as confused two weeks from now.

Well, it's a variation on an old idea. At least in the last game listed, where An Joyeong was White.

Click Here To Show Diagram Code

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

One point is that Black already had the extension at . is not one of those early 3-3 invasions that beginners are warned against.

Click Here To Show Diagram Code

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

If White continues with the slide for , then how to deal with the Black moyo is a question.

Click Here To Show Diagram Code

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

With the closer extension, was not uncommon, and often Black chose to wall off the moyo in exchange for letting White connect.

Click Here To Show Diagram Code

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

With the longer extension Chang Hao chose to enclose White in the corner. AFAIK, this is a new strategy for White with the longer extension.

_________________
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At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

There are 4 more examples in today's Chinese League:

http://www.go4go.net/go/games/sgfview/34019
http://www.go4go.net/go/games/sgfview/34023
http://www.go4go.net/go/games/sgfview/34034
http://www.go4go.net/go/games/sgfview/34040

It appears in two of the games above, the life&death situations in the corner were misread. Looks like pros are still experimenting this.

There was a detailed article about this corner pattern in a recent issue of Weiqi Tiandi, explaining quite clearly the ideas behind each move. I was quite impressed with the quick development the 3-3 invading side can have if they decided to sacrifice the corner.