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An anchor for saving a soon-to-be-atari stone - good?
Posted: Mon Apr 23, 2012 11:17 pm
by Sneegurd
A beginners setting. I'm black and played 7, because I thought I need a helping anchor for the marked stone, because of the upcoming Atari 8. So I connected it with 9 - was that a good idea? My beginners brain is thinking "well the marked black stone is somewhat useless". 7+9 maybe having future influence to the right. But not much influence, as they are directly connected. White has better influence to the top left corner and towards south-west.
What would you have done as move 7+?
Thank you!
$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . O . . .
$$ - . . O B 9 . .
$$ - . . . 8 7 . .
$$ - . . . . . . .
$$ - . . . . . . .
- Click Here To Show Diagram Code
[go]$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . O . . .
$$ - . . O B 9 . .
$$ - . . . 8 7 . .
$$ - . . . . . . .
$$ - . . . . . . .[/go]
Re: An anchor for saving a soon-to-be-atari stone - good?
Posted: Mon Apr 23, 2012 11:30 pm
by tchan001
You need to look at the situation more globally and ask yourself if it is really important to save that stone.
Remember White has to spend at least 2 more stones to capture that one stone.
Can you play elsewhere and get even more points as a result of not playing your anchor?
Even if White puts your Black stone in atari, you can still extend and run out towards the center if that is what you want.
So in my opinion, adding an anchor as you have makes you more committed to that stone/group and you will be less willing to sacrifice it to gain other bigger objectives if the opportunity appears.
I'd also advise you to take a look at the
tidbits in my go blog for some added inspiration to your study of go.
Re: An anchor for saving a soon-to-be-atari stone - good?
Posted: Tue Apr 24, 2012 12:43 am
by daal
Sneegurd wrote:
What would you have done as move 7+?
$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . d O . . .
$$ - . . O B c . .
$$ - . . . a b . .
$$ - . . . . . . .
$$ - . . . . . . .
- Click Here To Show Diagram Code
[go]$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . d O . . .
$$ - . . O B c . .
$$ - . . . a b . .
$$ - . . . . . . .
$$ - . . . . . . .[/go]
From your starting point above, you have a number of options. Here's my train of thought:
My black stone has only 2 liberties, it wants more. "a" or "c" would serve that purpose. White has a cutting point at "d." Let's keep an eye on that. Then I would probably play "a" because it puts more pressure on the weaker stone, the one closest to the edge. My stones then have 4 liberties, and now he has a cutting point, and I don't.
I basically wouldn't have considered playing "b" at all, because it doesn't help my liberty problem as well as just extending (note that in your diagram, your 3 stones have 4 liberties, which is worse than 2 stones having 4 liberties), and it leaves white with a forcing move - (assuming as TChan mentioned that I value the marked stone). BTW, in your diagram, the marked stone is not exactly doing nothing; it has created two cutting points.
Also, I have never heard the term "anchor" in a go context, but it's a word worth thinking about. An anchor is heavy and keeps you in one place. Heavy and immobile are not desirable properties for your stones.

edit: While I didn't consider Loons' b or c below (and loons is stronger than me), I did consider my "d," but forgot to mention it. This move is called a crosscut, and is a great way to get a nasty fight started. If you have some stones nearby, you will generally have an advantage in the ensuing fight. If you don't have support, crosscutting is often a good way to establish a position in an enemy-controlled area.
Re: An anchor for saving a soon-to-be-atari stone - good?
Posted: Tue Apr 24, 2012 1:44 am
by Loons
$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . a O b . .
$$ - . . O X . . .
$$ - . . c . . . .
$$ - . . . . . . .
$$ - . . . . . . .
- Click Here To Show Diagram Code
[go]$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . a O b . .
$$ - . . O X . . .
$$ - . . c . . . .
$$ - . . . . . . .
$$ - . . . . . . .[/go]
Now that black won the big ko fight, I'd've considered a or b or c, sabaki-style moves; and probably not tenuki yet (I think that might be heavy).
Re: An anchor for saving a soon-to-be-atari stone - good?
Posted: Tue Apr 24, 2012 6:02 am
by Sneegurd
Thank you. Oh, the liberties, usually they come to my mind late: if there's only one or two liberties left

.
At the moment I am avoiding cuts (a in Loons diagram) because I don't know how to continue properly. So my simple beginners thoughts are, the cut cannot be good because the opponent is in the same situation, but has the initiative/is one move ahead.
Re: An anchor for saving a soon-to-be-atari stone - good?
Posted: Tue Apr 24, 2012 10:23 am
by palapiku
Since there can't be a big ko fight on move 7, how did you get into the original position?
Re: An anchor for saving a soon-to-be-atari stone - good?
Posted: Tue Apr 24, 2012 11:40 am
by jts
$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . a O . . .
$$ - . . O B 9 . .
$$ - . . b 8 7 . .
$$ - . . . . . . .
$$ - . . . . . . .
- Click Here To Show Diagram Code
[go]$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . a O . . .
$$ - . . O B 9 . .
$$ - . . b 8 7 . .
$$ - . . . . . . .
$$ - . . . . . . .[/go]
What other people are saying is good. Lesson one:

is what got you into this bad situation. Lesson two: whether it's worth saving the stone in atari depends on the situation on the rest of the board.
However, no one has mentioned lesson three: if you do save the marked black stone, the reason to do so is because you hope to later exploit the cutting points at A and B, or at least force white to defend them. I would probably automatically save the the stones as a forcing move unless there were urgent moves elsewhere; knowing what side W wants to defend on is useful information. (That said, these are not particularly big cutting points, because they're so close to the edge.)
Compare this with the situation if W captures:
$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . O . . .
$$ - . . O C 0 . .
$$ - . . . 8 7 . .
$$ - . . . . . . .
$$ - . . . . . . .
- Click Here To Show Diagram Code
[go]$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . O . . .
$$ - . . O C 0 . .
$$ - . . . 8 7 . .
$$ - . . . . . . .
$$ - . . . . . . .[/go]
Now not only has W defended both cutting points in a single move, and left

looking completely wasted and inconsistent, but W can expand his corner extremely quickly, either along the top side or the bottom side, due to the versatility of the ponnuki shape.
Re: An anchor for saving a soon-to-be-atari stone - good?
Posted: Tue Apr 24, 2012 2:54 pm
by Sverre
jts wrote:$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . a O . . .
$$ - . . O B 9 . .
$$ - . . b 8 7 . .
$$ - . . . . . . .
$$ - . . . . . . .
- Click Here To Show Diagram Code
[go]$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . a O . . .
$$ - . . O B 9 . .
$$ - . . b 8 7 . .
$$ - . . . . . . .
$$ - . . . . . . .[/go]
(That said, these are not particularly big cutting points, because they're so close to the edge.)
Not particularly big? You'd tenuki and grab a big opening point now, if you were White?
Anyways,

is probably at least as bad as

$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . O 8 . .
$$ - . . O B . . .
$$ - . . . . 7 . .
$$ - . . . . . . .
$$ - . . . . . . .
- Click Here To Show Diagram Code
[go]$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . O 8 . .
$$ - . . O B . . .
$$ - . . . . 7 . .
$$ - . . . . . . .
$$ - . . . . . . .[/go]
Re: An anchor for saving a soon-to-be-atari stone - good?
Posted: Tue Apr 24, 2012 10:55 pm
by jts
Sverre wrote:jts wrote:$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . a O . . .
$$ - . . O B 9 . .
$$ - . . b 8 7 . .
$$ - . . . . . . .
$$ - . . . . . . .
- Click Here To Show Diagram Code
[go]$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . a O . . .
$$ - . . O B 9 . .
$$ - . . b 8 7 . .
$$ - . . . . . . .
$$ - . . . . . . .[/go]
(That said, these are not particularly big cutting points, because they're so close to the edge.)
Not particularly big? You'd tenuki and grab a big opening point now, if you were White?
Anyways,

is probably at least as bad as

$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . O 8 . .
$$ - . . O B . . .
$$ - . . . . 7 . .
$$ - . . . . . . .
$$ - . . . . . . .
- Click Here To Show Diagram Code
[go]$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . O 8 . .
$$ - . . O B . . .
$$ - . . . . 7 . .
$$ - . . . . . . .
$$ - . . . . . . .[/go]
I certainly would not! But whichever side white chooses to protect, the other cutting point can't immediately be exploited. That's what I meant. You disagree?
Re: An anchor for saving a soon-to-be-atari stone - good?
Posted: Wed Apr 25, 2012 12:34 am
by Sneegurd
palapiku wrote:Since there can't be a big ko fight on move 7, how did you get into the original position?
$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . 4 . . .
$$ - . . 6 5 9 . .
$$ - . . . 8 7 . .
$$ - . . . . . . .
$$ - . . . . . . .
- Click Here To Show Diagram Code
[go]$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . 4 . . .
$$ - . . 6 5 9 . .
$$ - . . . 8 7 . .
$$ - . . . . . . .
$$ - . . . . . . .[/go]
Re: An anchor for saving a soon-to-be-atari stone - good?
Posted: Wed Apr 25, 2012 1:05 am
by daal
Sneegurd wrote:palapiku wrote:Since there can't be a big ko fight on move 7, how did you get into the original position?
$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . 4 . . .
$$ - . . 6 5 9 . .
$$ - . . . 8 7 . .
$$ - . . . . . . .
$$ - . . . . . . .
- Click Here To Show Diagram Code
[go]$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . 4 . . .
$$ - . . 6 5 9 . .
$$ - . . . 8 7 . .
$$ - . . . . . . .
$$ - . . . . . . .[/go]
$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . b 4 a . .
$$ - . . c 5 . . .
$$ - . . d e . . .
$$ - . . . . . . .
$$ - . . . . . . .
- Click Here To Show Diagram Code
[go]$$B
$$ ------------------
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . . . . . .
$$ - . . b 4 a . .
$$ - . . c 5 . . .
$$ - . . d e . . .
$$ - . . . . . . .
$$ - . . . . . . .[/go]
While there are some situations in which you might want to touch an isolated stone, this isn't one of them, and there is a reason that this tends generally to be a bad idea. First of all, you immediately lose a liberty, and white has a number of options take advantage of this. The first idea is for white simply to strengthen his stone by extending to a or b. He will then have all of 5 liberties and be quite comfortable. He might also play c as he did in the game, which takes away one of your liberties and puts you in the position of having to strengthen your stone. If he afterwards fixes the weakness at b, his corner starts to get rather big and impregnable.
The long and short of it is that instead of playing

a move at d would have been more reasonable. It encroaches on the corner without putting yourself in danger. You still have all of your liberties and can move in several directions. If he plays c for example, you can play e and then you will be the one with a comfortable number of liberties.
Suggested reading: "basic instinct" on Sensei's Library.
Re: An anchor for saving a soon-to-be-atari stone - good?
Posted: Wed Apr 25, 2012 9:31 pm
by emeraldemon
Try posting the game for a review under "game analysis", many people are willing to help!
Re: An anchor for saving a soon-to-be-atari stone - good?
Posted: Wed Apr 25, 2012 10:40 pm
by Sneegurd
emeraldemon wrote:Try posting the game for a review under "game analysis", many people are willing to help!
Thank you. It's a 13x13 running game on DGS, so it will take some time until it's finished. I'll comment my game moves and think about posting it.