Another opening invasion-type question

PeterPeter · #1

The left side of this board seems to come up quite a bit in my games, in particular me as black facing this large white side moyo with no apparent way to break in.

Click Here To Show Diagram Code: [go]$$Bc $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O . e . . X . . . . . . . . . | $$ | . d O , . g . . . , . . . . . O . . . | $$ | . . . . . . f . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . c . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . W . b . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . a . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . O . X . X . . . , . . . O O O X X . | $$ | . . X . . . . . . . X . . X X X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

What is a strategy to deal with this?

I look at playing on A, but after white plays B, not much has been achieved.

Could an invasion at C survive? It looks difficult.

Is a probe at D playable? I think I could get either a small corner or side base from there.

I ended up playing on E, then after white's F, still not much has been achieved. I decided not to cut at G, as it just seemed to strengthen white.

jts · #2

I would play in the upper right corner instead. It only has one move in it; the rule of thumb is to go for the emptiest part of the board. Lower left has six moves, upper right has one move. By the way, I think W should expand his territory with your "a" rather than the marked point.

Click Here To Show Diagram Code: [go]$$Bc $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O . C . . X . . . . . . . . . | $$ | . . O , . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . C . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . W . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . O . X . X . . . , . . . O O O X X . | $$ | . . X . . . . . . . X . . X X X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

However, in the grand scheme of things the move you chose (making a solid base for your stones in front of the area where you're worried W will make lots of territory) shows sound judgment about how to "deal with" the situation. Just remember you don't always have to deal with absolutely everything your opponent does. If he keep obstinately playing slow moves on one side of the board, he will get points there... just not as many points as you get elsewhere.

Edit: I should also say that the stones in the lower right corner do not look finished. Quite possibly playing there is larger than a merely "big" move in the upper right. I couldn't tell you where without thinking longer about it, though.

skydyr · #3

I agree with jts's assessment of how white should have played. White's bottom left in the original diagram looks overconcentrated.

That said, the first question that comes to my mind is "Does black need to invade?" The only way to know is to count:

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I think we can safely call the white left maybe 45 points if he gets it all without expanding, and white doesn't have any other territory to speak of on the board. Black's bottom right is at least 20 points, and the bottom left should get another 10-20 without too much trouble. I think black also has better prospects in the top right if he plays there first.

Click Here To Show Diagram Code: [go]$$Bc $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . 7 . . . | $$ | . . . . O . e . . X . . . 1 . . 8 . . | $$ | . d O , . g . . . , . 9 . . . O . . . | $$ | . . . . . . f . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . 2 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . c . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . W . b . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . 5 . 3 . . | $$ | . . O . a . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O 4 . | $$ | . O . X . X . . . , . . . O O O X X . | $$ | . . X . . . . . . . X . . X X X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

A sequence like this might be enough to bring the game into parity, as white's wall doesn't have any eyes yet, has ladder aji (:b5: breaks the ladder and the net), and doesn't have a good target to counterattack. Black can also solidify the group on the top later on with the sequence from 7 to 9. At this point, A and G or E would be great reduction moves to limit what white can get on the left side, and it's hard to see how white will get a lot of points out of the right side of the board.

PeterPeter · #4

jts wrote:

I would play in the upper right corner instead. It only has one move in it; the rule of thumb is to go for the emptiest part of the board.

That was indeed my next idea, but unfortunately my choice was to invade at 3-3 and after the joseki, my small base at the top felt under constant threat.

Click Here To Show Diagram Code: [go]$$Bc $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . O X X . . | $$ | . . . . O . X . . X . . . W . O X . . | $$ | . . O , . . . . . , . . . . . O X . . | $$ | . . . . . . O . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . O . X . X . . . , . . . O O O X X . | $$ | . . X . . . . . . . X . . X X X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

skydyr · #5

PeterPeter wrote:

jts wrote:

I would play in the upper right corner instead. It only has one move in it; the rule of thumb is to go for the emptiest part of the board.

That was indeed my next idea, but unfortunately my choice was to invade at 3-3 and after the joseki, my small base at the top felt under constant threat.

Click Here To Show Diagram Code: [go]$$Bc $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . O X X . . | $$ | . . . . O . X . . X . . . W . O X . . | $$ | . . O , . . . . . , . . . . . O X . . | $$ | . . . . . . O . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . O . X . X . . . , . . . O O O X X . | $$ | . . X . . . . . . . X . . X X X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Yeah... invading gets white strong on the outside to attack on the top and right sides. It's better to approach the top right normally instead.

jts · #6

I don't think the invasion is that awful. I do like skydr's plan for the upper right better than the invasion, especially because it offers you a way to exploit W's weaknesses in the lower right, but your top group doesn't bother me too much.

Click Here To Show Diagram Code: [go]$$Bc $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . O X X . . | $$ | . . . . O . B . . B . . . O . O X . . | $$ | . . O , . . . . . , . . . . . O X . . | $$ | . . . . . . O . . 1 . . . . . . O X . | $$ | . . . . . . . . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . O . X . X . . . , . . . O O O X X . | $$ | . . X . . . . . . . X . . X X X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

You have sente, so (since you have correctly intuited that your group could be harassed later) you can defend the group in the manner of your choosing. (The marked point is my first guess, but I haven't done any reading.) Taking a corner and giving your opponent a wall that faces a group that's nearly settled is a sensible direction of play for you.

Bill Spight · #7

Click Here To Show Diagram Code: [go]$$Bc $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . X . . . . . . . . . | $$ | . . O , . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . O . X . X . . . , . . . O O O X X . | $$ | . . X . . . . . . . X . . X X X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

The opening has pretty well reached the point where the big places, i. e., the points where a stone makes the loudest sound, have been occupied. A possible exception is on the left of the top side.

Click Here To Show Diagram Code: [go]$$Wc $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O . . 1 . B . . . . . . . . . | $$ | . . O , . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . O . X . X . . . , . . . O O O X X . | $$ | . . X . . . . . . . X . . X X X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

, small extension though it may be, threatens the :bc:

stone.

Click Here To Show Diagram Code: [go]$$Bc $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O . 1 . . X . . . . . . . . . | $$ | . . O , . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . O . X . X . . . , . . . O O O X X . | $$ | . . X . . . . . . . X . . X X X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

So Black's extension in the actual game is quite reasonable.

As for urgent plays:

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White would like to extend to :w1:

, making a base for the :wc:

stones and threatening the :bc:

stone.

Click Here To Show Diagram Code: [go]$$Bc $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . X . . . . . . . . . | $$ | . . O , . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . 1 . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . W . . | $$ | . O . X . X . . . , . . . W W W X X . | $$ | . . X . . . . . . . X . . X X X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

So the attack with :b1:

is good. It has the extra attraction that most kyu players and a number of dan players do not know how to handle the :wc:

stones.

There is also an urgency to the left side.

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A play like :w1:

would make it very difficult to invade.

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reduces the left side and supports :b3:

.

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To the probe at :b1:

White replies with :w2:

. Black has a later play in the corner, but, speaking for myself, I do not like this exchange.

Click Here To Show Diagram Code: [go]$$Bc $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . X . . . . . . . . . | $$ | . 4 O , . . . . . , . . . . . O . . . | $$ | . . 1 2 8 . . . . . . . . . . . . . . | $$ | . . 3 7 . . . . . . . . . . . . . . . | $$ | . . . . . 9 . . . . . . . . . . . . . | $$ | . . 5 . . . . . . . . . . . . . . . . | $$ | . 6 . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . 0 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . O . X . X . . . , . . . O O O X X . | $$ | . . X . . . . . . . X . . X X X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Another play is the side attachment at :b1:

. Then

-

is usual.

-

is one possible follow-up. But then after :w10:

White in the bottom right looks better to me than Black in the top left.

I am inclined, then, to go with the attack in the bottom right.

Another opening invasion-type question

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