Kataoka played sanrensei.

Click Here To Show Diagram Code

[go]$$Wcm10 White sanrensei
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 1 . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . X . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . 2 O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

As we now know, White sanrensei is seldom right, if ever, but way back then it was certainly an attractive move.

Takemiya replied with the attachment, , but Elf thinks that that loses 11% to simply occupying the 3-3.

Click Here To Show Diagram Code

[go]$$Bcm11 Mainline for
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 3 . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 6 4 . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . O . . . . . , . . . 7 . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . X . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . 2 . . O . . 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Black occupies one 3-3 point and then switches to a footsweep in the other corner. Next, braves the deep.

For Elf prefers to invade a corner.

Click Here To Show Diagram Code

[go]$$Wcm10 White invades a corner
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 6 5 7 . . |
$$ | . . . . . . . . . . . . . O 9 2 1 . . |
$$ | . . . O . . . . . , . . . . . X 3 . . |
$$ | . . . . . . . . . . . . . X . 4 8 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . X . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . a . . O . . . . . |
$$ | . . . . . . . . . . . . . . 0 . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

After the invasion there follows a placid joseki, and then plays the footsweep in the other corner. extends to a.

These differences in evaluation are really what the opening is about.

Speculatively:
Current position:
1. Seems that the 3-3 invasions R3, R17 are standard and good here. M4 also comes to mind. F3 as well. R6 seems overplay.

Opp to play
1. L4?

Past:
1. W ahead a little

Check:
1. I checked this shape in the past. Another variation is R17 R16 Q17 P16 N18
2. I didn't know B's follow up was 3-3.