This happened in one of my IGS games, last night, and I did not respond correctly. What should black do? (Black wants to keep outward influence or take the left side. Reclaiming the corner is playable too if white is left thin but black has a deep moyo on the right, center, and, ideally, doesn't want white to have too much power to attack it.)

Click Here To Show Diagram Code

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

Last night, I played at a and lost the whole corner. I won the game, ultimately, but felt that this was my biggest mistake. (If a is the right response, how does it go?)

Click Here To Show Diagram Code

[go]$$Wc Black to Respond
$$ | . . . X . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . b . . . . . .
$$ | . . . a . . . . .
$$ | . 6 4 5 . . . . .
$$ | . . 3 X . . O . X
$$ | . . 1 2 . f . . .
$$ | . . e c d . . . .
$$ | . . . . . . . . .
$$ ------------------[/go]

This is my first instinct - if White "a" then Black "b", if White "c" then Black "d", White "e", Black "f"

Click Here To Show Diagram Code

[go]$$Wc Black to Respond
$$ | . . . X . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . 4 . . . . . .
$$ | . . 3 X . a a . X
$$ | . . 1 2 . a a . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ ------------------[/go]

before anything else, it should be noted that whenever white has a stone at one of the points marked 'a', the invasion at 1 is considerably more powerful and 4 is generally a mistake.

Click Here To Show Diagram Code

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

Simple but pretty effective

Click Here To Show Diagram Code

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

this actually works fine as well

_________________
Tactics yes, Tact no...

Needs the ladder, though

Click Here To Show Diagram Code

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

I feel the direct block is safer; there's a squeeze but I don't know if it does White much good

Click Here To Show Diagram Code

[go]$$Bc Where are you going with this, White?
$$ | . . . X . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . 1 X O 6 . . . .
$$ | . . O X 5 8 O . X
$$ | . . O X 4 7 . . .
$$ | . . . 2 3 . . . .
$$ | . . . . . . . . .
$$ ------------------[/go]

Hmm... I wondered if 4 was actually the mistake. How should black have responded to 1?

Click Here To Show Diagram Code

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

This is one way to play, assuming that hane with 4 isn't playable and that you're OK with thickness facing the right and center.

Click Here To Show Diagram Code

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

I'm just curious that no-one has mentioned black's first move at C2? It's not easy, but is there an obvious reason black needs to start by thinking about b5 (or 4) ?

(I don't see white being fast enough to live in the corner and get an ok result outside, but I haven't had my coffee yet so who knows).

_________________
Revisiting Go - Study Journal
My Programming Blog - About the evolution of my go bot.

Yes, Loons, is a very natural first feeling and shape move:

Click Here To Show Diagram Code

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

W's shape is not good:

Click Here To Show Diagram Code

[go]$$B
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . # O . . . . .
$$ | . . W # . . O . X
$$ | . . W # . . . . .
$$ | . . # . . . . . .
$$ | . . . . . . . . .
$$ -------------------[/go]

questions on EdLee's last diagram
First I fully agree that white shape seems bad, but:
It seem (just seems, read nothing) white can easily live by crawling a few steps on second line, and keep sente (because black has to something about white's cutting stone). Is this correct? And then, we all know crawling on second line is terrible, etc but considering that it was 3-3 invasion right from the start anyway, would white
result be so bad?

_________________
If you say no, Elwood and I will come here for breakfast, lunch, and dinner every day of the week.

Transposition.



White has transposed to a joseki that seems ill-advised with the Black stones already on the side. The play through follows that joseki. Then, instead of pushing again, White lives in the corner. The result looks pretty bad for White.

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

Visualize whirled peas.

Everything with love. Stay safe.

I like Bill's outcome for black - it looks favourable in general - but in the actual game that raised this question, I think it would have been a thing of beauty and white would surely have resigned immediately.