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determining the value of moves
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Author:  standardtrickyness [ Fri Apr 01, 2011 9:58 pm ]
Post subject:  determining the value of moves
How do you determine the value of a move? As well which stones can be sacrificed? For example in the sgf file with the joseki poorly played my instinct was to play the last move on the second line to jump out but apparently its bad. I'm not sure about the value of broken influence. In the other example in the sgf file I thought that playing B15 was too many moves to capture those two stones.

hmm can someone open my sgf file and edit this?

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Author:  EdLee [ Sat Apr 02, 2011 1:52 am ]
Post subject: 
Yes. :) I don't know why the URL method did not work for you,
but inline SGF and SGF-Full both work:
Author:  Toge [ Sat Apr 02, 2011 3:57 am ]
Post subject:  Re: determining the value of moves
standardtrickyness wrote:
How do you determine the value of a move?


- There are two cases where value can be determined: in yose and in fuseki. Yose values are more precise. You can get it by calculating the point gain when you opponent plays a move and when you play it, then divide it by two. If the sequence is sente, multiply the value by two. Double sente - that is sente for both players - are extremely important to grab as soon as possible.

Top left: black gains 2 points by playing "a". White gains 12 points by playing "a". Move "a" is worth (2 + 12) / 2 = 7 points
Right side: example of double-sente. White "b" prevents black "c" and vice versa.
Bottom left: marked white stones have served their purpose and have no potential for development. This means that black shouldn't try to capture them until late at the game and white shouldn't play to save them. The important thing is to determine status of the rest of the stones. However, if the status of the board changes so that cut at "d" becomes feasible, saving these stones might be sente.
Click Here To Show Diagram Code
[go]$$c
$$ ---------------------------------------
$$ | . X O . . . . . . . . . . . . . . . . |
$$ | a X O . . . . . . . . . . . . . . . . |
$$ | . X O . . . . . . . . . . . . . . . . |
$$ | X X O , . . . . . , . . . . . X . . . |
$$ | O O O . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . , . . . . . , . . . . . X X X b |
$$ | . . . . . . . . . . . . . . . O O O c |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . X . . . . . . . . . . . . O . . . |
$$ | . X . . . . . . . . . . . . . O . . . |
$$ | . O X X X X X X d , . . . . . O . . . |
$$ | . O O O O X P P X . . . . . . . . . . |
$$ | . . . . . O . . X . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Fuseki is a bit trickier to count. Basically value of move depends on what it accomplishes.
1. Build base / steal base
2. Connect groups / cut them apart
3. Focal point between two territories is twice as big as simple land grab
4. Attack weak group / make your weak group strong
5. etc.

Moves that accomplish several objectives are the ones you should be playing.

standardtrickyness wrote:
As well which stones can be sacrificed?


- Moves that have served their purpose can be abandoned. For instance, stones that are cutting two weak groups are important. They make attacks possible. If both groups are alive by themselves even with cutting stones in place, those stones can be sacrificed. Also those stones can be safely sacrificed that have no potential to develop. See above diagram.
Author:  emeraldemon [ Sat Apr 02, 2011 7:19 am ]
Post subject:  Re: determining the value of moves
I do think L2 (last move in lower right) is a mistake. It just doesn't do that much for you. Two things occur to me: splitting with a jump like N5 or O5, or taking white's base around R10, since white didn't take it. You say L2 was your instinct, but the only "instinctual" benefit I see is that black isn't sealed in. Is that why you played it?
Author:  standardtrickyness [ Sun Apr 03, 2011 11:29 am ]
Post subject:  Re: determining the value of moves
yes it is um well also I personally don't like influence in a L shape because it seems to give the opponent too much territory and is hard to make into a good moyo (in my 9-6k opinion) how many points is it worth? because if it is ignored then whites influence is reduced. How many points is that move worth at this stage of the game also for the 2nd example should those two stones be sacrificed with a move like say c14?
Author:  Dusk Eagle [ Sun Apr 03, 2011 12:01 pm ]
Post subject:  Re: determining the value of moves
standardtrickyness wrote:
yes it is um well also I personally don't like influence in a L shape because it seems to give the opponent too much territory and is hard to make into a good moyo (in my 9-6k opinion) how many points is it worth? because if it is ignored then whites influence is reduced. How many points is that move worth at this stage of the game also for the 2nd example should those two stones be sacrificed with a move like say c14?


I'm sorry, but I'm having a tough time understanding you. Could you give an example of the L-shape influence you're talking about? I can't tell if you're referring to the bottom right sequence or not.

For your second question, I don't quite understand how C14 would be sacrificing any stones. Could you explain? However, the fundamental problem in the upper-left is :b4: below. Letting white get :w5: is physically painful - I don't even like to think about that happening to me. :b4: should probably be at :w5:, to stay ahead in the pushing race. After white gets to hane on the head of the two black stones in your sgf, the result is going to be awful for black no matter what he does.

Click Here To Show Diagram Code
[go]$$Wcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 1 3 . . . . . . . . . . . . . . . |
$$ | . . 4 2 5 . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Author:  emeraldemon [ Sun Apr 03, 2011 12:28 pm ]
Post subject:  Re: determining the value of moves
There's an article about the 3-3 joseki here:

http://senseis.xmp.net/?33PointShoulderHit


Also SL has some stuff about this two-space jump in the lower right, but it needs some cleanup it looks like:

http://senseis.xmp.net/?BQM25

http://senseis.xmp.net/?34PointHighApproachInsideContact%2FDiscussion#toc4
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