I think that we need to realize the context here. Katago calculates that
is a mistake worth several % in winrate and a few tenths of a point. I was surprised that GoGoD has 137 examples of this fuseki. The normal human continuation has been to simply enclose the upper right, mainly making the small knight shimari. Katago calculates that this is around 5% worse than playing b at the 3-3 point in the lower left. The approach at
is the second most popular idea in human play. However, there are only two games with Black replying to
with
. Instead Black more often initiates some form of the nadare joseki with c in place of
. Katago calculates that White should reply to
locally. However, after
, Black should switch to b in the lower left. The difference is not large but Black is still better of by being the first to play there. When Black connects instead, White would be better off to enclose the bottom left and when White extends at the top instead, Black should take the last opportunity to invade.
- Click Here To Show Diagram Code
[go]$$Bc Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 2 . 0 . . . . . . . . a . . . . |
$$ | . . 8 c . . . . . , . . . . . , 1 . . |
$$ | . . 6 5 . . . . . . . . . . . . . . . |
$$ | . . 7 . . . . . . . . . . . . . . . . |
$$ | . . . 9 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 4 . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . b . . . . . . . . . . . . 3 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
At this point there are two unfinished corners for Black to choose from. Blue is the large knight's enclosure at the bottom right while the same large knight enclosure in the top right is a close competitor. But there is something else here as well. Katago calculates that White's invasion at a on the left side is a very important point. In the actual game White never plays there. However, looking at katago's analysis the issue persists. This does not appear in human play.
- Click Here To Show Diagram Code
[go]$$Bc Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . O . . . . . . . . . . . . . |
$$ | . . O . . . . . . , . . . . . , X . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . a . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . O . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Policy for White when Black takes the bottom.
If we run a search in GoGoD on the left side of the board in the game. There are 260 hits. Only 7 of the games have the next play at k below. The
ten plays that appear more frequently are marked a through j (variously for White and Black, e.g. White's most frequent next play in this area is the extension at a while Black's is the attachment at b). In reality play normally moves elsewhere, often for considerable lengths of time.
- Click Here To Show Diagram Code
[go]$$Wc Continuations
$$+ - - - - - - -
$$| . . . . . . .
$$| . . . . . . .
$$| . . . O . O .
$$| . . O , i . f
$$| . . O X . . g
$$| . . X . . . j
$$| . . . X . . .
$$| . . k . . . .
$$| . . . . . . .
$$| . . . , . . .
$$| . . X . . . .
$$| . . . . . . .
$$| . . e . . . .
$$| . . . . . . .
$$| . . O . . . .
$$| . . . , . . h
$$| . . . O b c a
$$| . . . d . . .
$$| . . . . . . .
$$+ - - - - - - -[/go]
_________________
Dave Sigaty"Short-lived are both the praiser and the praised, and rememberer and the remembered..."
- Marcus Aurelius; Meditations, VIII 21