This example is from a recent game of mine in which I played the black stones. I'm asking the question to help myself better understand the basic principle behind the power of influence. If you were playing black, would you expect to kill this stone and how would you respond? If you couldn't kill it, how would you manage to make profit from attacking it?

Click Here To Show Diagram Code

[go]$$c Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . X , . O . . . , . . . . . X . . . |
$$ | . . X O . . . . . . . . . . . . . . . |
$$ | . O O . . . O . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . O O . . . . . . . . . . . . . |
$$ | . . . O X X . . . . . . . . . . . . . |
$$ | . . O . O X . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . . O X X . . . . @ . . . . . , . . . |
$$ | . . O . . . . . . . . . . . . X . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

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Thinking like a go player during a game of chess is like bringing a knife to a gun-fight. Thinking like a chess player during a game of go feels like getting knifed while you're holding a gun...

White's move is fine and it should not die. Ideally, black would approach from the right to force it to run or live in a cramped area, and black would profit on the right side and with central thickness. Unfortunately, black's group on the left is not as thick as it looks at first glance, so black will have to keep it in mind as black is attacking. Approaching from the left, though, feels overconcentrated. There may be a case for some kind of fencing in move like a cap or L6 or something, but I do not feel qualified to make it if it exists. Maybe black can also get away with just making a corner enclosure at Q5 and seeing what white does.

In a perfect world, black would have played something on the bottom side to work with the wall on the left prior to white's jumping in here, but perhaps there was a good reason for that not to happen. In any case it's worth bearing in mind that white's potential is mostly tapped out now with the 30-40 points on the left. Black has maybe 10 in the top left corner, so black only needs to get 30 more points than white does in the rest of the game to win, which looks quite doable.

I would not expect to kill White. Instead, I would try to drive White towards my thickness (indirectly making profit from the wall) and make a heavy shape, trying to profit on the right side. However, it seems to me that B's thickness is not that powerful either, so I'd be cautious. I would try to do it with L5 and see how White responds, personally.

Click Here To Show Diagram Code

[go]$$c Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . X , . O . . . , . . . . . X . . . |
$$ | . . X O . . . . . . . . . . . . . . . |
$$ | . O O . . . O . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . O O . . . . . . . . . . . . . |
$$ | . . . O X X . . . . . . . . . . . . . |
$$ | . . O . O X . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . B . . . . . . . . |
$$ | . . O X X . . . . O . . . . . , . . . |
$$ | . . O . . . . . . . . . . . . X . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Inseong has a lecture which I find to be related to this, which he did at the US Go Congress this last year.

The lecture is actually about attacking - how to attack a weak group. The basic idea is that there is not only one objective that you can achieve from attacking a group - there are several possibilities:
1.) Killing the group - if you can attack the group and be sure to kill it - well, great.
2.) Make territory or moyo by driving the group in a particular direction - in this case, you might not kill the stone, but you get a lot of profit from all the forcing moves you can use.
3.) Defending your own groups - maybe you have a weak group yourself, and you can use forcing moves against the group to strengthen your own group.
4.) No clear way to profit right now - if there's no clear way to make territory, influence, kill the group, strengthen your own group, or otherwise profit from attacking... Then don't decide right now. Leave the group weak, and play another big point.

So the "power of influence" is a multi-faceted concept. Influence is certainly useful - but it can be used in many ways.

The important thing is to come up with a strategy - what are you trying to achieve, and will you be able to achieve it? The numbered list above are some ideas you can consider when trying to utilize your influence and attack a group.

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be immersed

It should not die. Not even close. But in my opinion it is one point to the left of where is should be and black can take advantage of this fact to make a larger moyo to the right than he really deserves.

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Still officially AGA 5d but I play so irregularly these days that I am probably only 3d or 4d over the board (but hopefully still 5d in terms of knowledge, theory and the ability to contribute).

I don't really like that move. It does not feel either high enough to be a good reducing move ( as Sol's reply shows ) nor low enough to be a good invasion.
It appears that you did not really decide whether you wanted to reduce or invade before you played the stone, and just sort of plopped it down in the general area.

Years ago, there was a really good book entitled "Keshi and Uchikomi". I recommend it if you can get a copy.

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He said he was black, so he didn't make the move. Figuring out how best to attack a misplaced stone is something we SDKs often struggle with.

(For what it's worth, I probably would have ended up playing M3 to deny the stone a base while beginning to make territory on the bottom / lower right corner. But based on Solomon's reply, perhaps my instincts about whether to attack from the top or bottom were misplaced.)

M4 is the only answer in my opinion.

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Still officially AGA 5d but I play so irregularly these days that I am probably only 3d or 4d over the board (but hopefully still 5d in terms of knowledge, theory and the ability to contribute).

Oooops! Sorry, OP

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Help make L19 more organized. Make an index: https://lifein19x19.com/viewtopic.php?f=14&t=5207

I played M4 in the game and attempted to make a moyo on the right side. The reason I ask though is because of the proverb "don't play too close to thickness" and it seemed that white had violated this. Punishing poorly placed moves is a kyu weakness indeed...

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Thinking like a go player during a game of chess is like bringing a knife to a gun-fight. Thinking like a chess player during a game of go feels like getting knifed while you're holding a gun...

It sounds like you had a good strategy.

IMO, White did play too close to thickness, but only a bit.

As for punishing poorly placed stones, only some poorly placed stones are self-punishing. This one needs a pincer from the right.

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

Visualize whirled peas.

Everything with love. Stay safe.

Good job with m4, but what were the next half dozen moves or so? In this kind of situation one direction mistake can lose a lot. Btw skydyr said white has 30-40 points on the left, it looks to me that white will likely get nearer 50 there. I'm wondering how that position happened; I suspect black made a mistake somewhere. g9 is an important point.

Influence needs an extension, so something has definitely gone awry for black before this. Left side is too huge + solid. The position would be better balanced if black had a stone around the star point on the lower side. White's move isn't perfectly placed, but good enough to nullify blacks influence and get a comfortable game with all those points.

Some walls need an extension. Walls with eye potential do not.

Edit: That said, I agree that White has taken the lead.

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

Visualize whirled peas.

Everything with love. Stay safe.

Click Here To Show Diagram Code

[go]$$c Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . X , . O . . . , . . . . . X . . . |
$$ | . . X O . . . . . . . . . . . . . . . |
$$ | . O O . . . O . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . O O . . . . . . . . . . . . . |
$$ | . . . O X X . . . . . . . . . . . . . |
$$ | . . O . O X . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . . O X X . . . . O . . 1 . . , . . . |
$$ | . . O . . . . . . . . . . . . X . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I would play this way. The black wall to the left has shape that is a bit disappointing, in a sense. When expectations are lowered, one should play in a steady, constructive way, hoping for a bit of momentum.

Click Here To Show Diagram Code

[go]$$c Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . X , . O . . . , . . . . . X . . . |
$$ | . . X O . . . . . . . . . . . . . . . |
$$ | . O O . . . O . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . O O . . . . . . . . . . . . . |
$$ | . . . O X X . . . 3 . . . . . . . . . |
$$ | . . O . O X . . . . . . . . . . . . . |
$$ | . . . O X . a . . 2 . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . . O X X . . . . O . . 1 . . , . . . |
$$ | . . O . . . . . . . . . . . . X . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

This way should be OK for Black, as long as there is a plan for when White peeps at a. White does have some ko threats top left, I think (e.g. B17). Black can do some serious damage by winning the ko twice. Which isn't yet on the cards.

Click Here To Show Diagram Code

[go]$$c White to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . X , . O . . . , . . . . . X . . . |
$$ | . . X O . . . . . . . . . . . . . . . |
$$ | . O O . . . O . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . O O . . . . . . . . . . . . . |
$$ | . . . O X X . . . X . . . . . . . . . |
$$ | . . O . O X . . . . . . . b . . . . . |
$$ | . . . O X . . . . O . 6 . . . . . . . |
$$ | . . . O X . . . . . . 4 5 . . . . . . |
$$ | . . O X X . . 7 . O . . X . . , . . . |
$$ | . . O . . . . . . . . . . . . X . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

My idea as White would be to lie in wait for Black, just building some shape (at the cost of some points). Now would be reasonable, just considering the base of two groups. Black b would be nice, but it is White's turn.