Page 12 of 14

Re: Araban vs Magicwand II

Posted: Mon Nov 28, 2011 8:22 pm
by Magicwand
Loons wrote:@Magicwand:
Sorry about the vague question;
What sort of result are you expecting on the left, once it becomes settled?

i will be honest...i could not comeup with anything better so i played only move i think make sense.
everyone knows that i can not kill that group. so i will use his weakness to settle my side group in sente.
i really dont have any solid plan now but if i can get my sente i will keep my lead.
i will post soon as i think of something.

Re: Araban vs Magicwand II

Posted: Mon Nov 28, 2011 8:48 pm
by Joaz Banbeck
For observers:
Loons wrote:
Click Here To Show Diagram Code
[go]$$Bcm61 Prisoners: white 2 black 0
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . X . . O . O . . . |
$$ | . X O O . . . . . . . . O O . O O X . |
$$ | . . X , O . . O . X . X . . O X X . . |
$$ | . X . . . . . O X . . . . X X . . X . |
$$ | . . . X . . . . X . . O . . O . . . . |
$$ | . . . . X . O . . . . . . . . X . . . |
$$ | . . Q . . . . . X . . X . O . X . . . |
$$ | . . . . . . . . . X X O O . . . . . . |
$$ | . . . , . . . . . , O X . . . , . . . |
$$ | . . . Q . . . . . . X X O O . . . . . |
$$ | . . . . . . . . . . . a . . . . . . . |
$$ | . . 9 . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 5 . . . . . . . . . . . . O . . . . |
$$ | . X 4 O . . . . . , . . O . O X X . . |
$$ | . 6 8 . . O . . . . . . . O X . . . . |
$$ | . 7 . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
We can expect this, right?...


I don't think that Araban will play 67 anyplace in the corner if MW takes the corner with 66. It is aji keshi. I suspect that Araban will reserve the option to play C3 as a ko threat. ( No matter how white defends, black then gets two potentially group-saving threats down there. )

I'm expecting that it will not come to that because MW will not take the corner at all:
Click Here To Show Diagram Code
[go]$$Bcm65 Prisoners: white 2 black 0
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . X . . O . O . . . |
$$ | . X O O . . . . . . . . O O . O O X . |
$$ | . . X , O . . O . X . X . . O X X . . |
$$ | . X . . . . . O X . . . . X X . . X . |
$$ | . . . X . . . . X . . O . . O . . . . |
$$ | . . . . X . O . . . . . . . . X . . . |
$$ | . . O . . . . . X . . X . O . X . . . |
$$ | . . . . . . . . . X X O O . . . . . . |
$$ | . . . , . . . . . , O X . . . , . . . |
$$ | . . . O . . . . . . X X O O . . 8 . . |
$$ | . . . . . . . . . . . a . . . . . . . |
$$ | . . 2 . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 1 . . . . . . . . . . . . O . . . . |
$$ | . X O O . . . . . , . . O . O X X . . |
$$ | . 7 3 4 . O . . . . . . . O X . . . . |
$$ | . 5 6 . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Taking the outside with C7 leads to a position in which white has lots of influence and no weak groups and sente. That seems to match well with MW's stylistic preferrences.

Re: Araban vs Magicwand II

Posted: Mon Nov 28, 2011 10:10 pm
by Jedo
to joaz
I disagree that :b67: is aji keshi. I see it as a probe to force white to commit to either letting black have a nice endgame attach or letting black have powerful aji to draw on (if white chooses to block). If black waits, it may be too easy of a choice for white.

Your second diagram is interesting, but if MW intended to play that way, might he instead have played

Click Here To Show Diagram Code
[go]$$Bcm61 Prisoners: white 2 black 0
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . X . . O . O . . . |
$$ | . X O O . . . . . . . . O O . O O X . |
$$ | . . X , O . . O . X . X . . O X X . . |
$$ | . X . . . . . O X . . . . X X . . X . |
$$ | . . . X . . . . X . . O . . O . . . . |
$$ | . . . . X . O . . . . . . . . X . . . |
$$ | . . O . . . . . X . . X . O . X . . . |
$$ | . . . . . . . . . X X O O . . . . . . |
$$ | . . . , . . . . . , O X . . . , . . . |
$$ | . . . O . . . . . . X X O O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 4 . . . . . . . . . . . O . . . . |
$$ | . 3 . O . . . . . , . . O . O X X . . |
$$ | . . . . . O . . . . . . . O X . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Re: Araban vs Magicwand II

Posted: Tue Nov 29, 2011 3:55 am
by Tooveli
Re: 67

Click Here To Show Diagram Code
[go]$$Bcm61 Prisoners: white 2 black 0
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . X . . O . O . . . |
$$ | . X O O . . . . . . . . O O . O O X . |
$$ | . . X , O . . O . X . X . . O X X . . |
$$ | . X . . . . . O X . . . . X X . . X . |
$$ | . . . X . . . . X . . O . . O . . . . |
$$ | . . . . X . O . . . . . . . . X . . . |
$$ | . . Q . . . . . X . . X . O . X . . . |
$$ | . . . . . . . . . X X O O . . . . . . |
$$ | . . . , . . . . . , O X . . . , . . . |
$$ | . . . Q . . . . . . X X O O . . . . . |
$$ | . . . . . . . . . . . a . . . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 5 . . . . . . . . . . . . O . . . . |
$$ | . X 4 O . . . . . , . . O . O X X . . |
$$ | a 6 8 . . O . b . . . . . O X . . . . |
$$ | . 7 . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I was taught 67 as joseki. It's meant to be a good probe and good timing in this sequence.
It is hard for White to descend at a because of the weaknesses it creates (eg. Black plays at b). Forcing White to play 68 early leaves connecting underneath in the corner as big endgame for later.

Re: Araban vs Magicwand II

Posted: Tue Nov 29, 2011 2:06 pm
by Uberdude
Tooveli wrote:Re: 67

Click Here To Show Diagram Code
[go]$$Bcm61 Prisoners: white 2 black 0
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . X . . O . O . . . |
$$ | . X O O . . . . . . . . O O . O O X . |
$$ | . . X , O . . O . X . X . . O X X . . |
$$ | . X . . . . . O X . . . . X X . . X . |
$$ | . . . X . . . . X . . O . . O . . . . |
$$ | . . . . X . O . . . . . . . . X . . . |
$$ | . . Q . . . . . X . . X . O . X . . . |
$$ | . . . . . . . . . X X O O . . . . . . |
$$ | . . . , . . . . . , O X . . . , . . . |
$$ | . . . Q . . . . . . X X O O . . . . . |
$$ | . . . . . . . . . . . a . . . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 5 . . . . . . . . . . . . O . . . . |
$$ | . X 4 O . . . . . , . . O . O X X . . |
$$ | a 6 8 . . O . b . . . . . O X . . . . |
$$ | . 7 . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I was taught 67 as joseki. It's meant to be a good probe and good timing in this sequence.
It is hard for White to descend at a because of the weaknesses it creates (eg. Black plays at b). Forcing White to play 68 early leaves connecting underneath in the corner as big endgame for later.


Yes, the 67 clamp probe is standard (it is played immediately in about 300 of 500 games in GoGoD with this corner shape), but it is not always a good move according to Guo Juan. The point is it asks white whether he wants to connect or descend.

Actually white has a 3rd choice, tenuki, say to play a pincer on the left side, forcing black to capture the stone and make eyes and corner profit so black would usually be content with this; if he is not (e.g. because the white pincer makes some huge left side) then he should extend down the side first as the clamp is his privilege: white would usually make a kick/block/checking extension to stop black extending further down the side, and then black could clamp.

Click Here To Show Diagram Code
[go]$$ Descent: good points, bad aji
$$ | . . . . . . . . . . .
$$ | . . . f . . . . . . .
$$ | . . . . . . . . . . .
$$ | . 3 . b . . . . . . .
$$ | . 1 2 O . . . . . , .
$$ | 6 4 c . . O . a . . .
$$ | . 5 . d . e . . . . .
$$ | . . . . . . . . . . .
$$ ------------------------[/go]


If white descends then black loses yose (in yose black could exchange 6 for 5), in exchange for white having bad aji from the cut left at c. As others mentioned, one use of this aji is the point a, if white makes a pincer on it then black has the placement at d which makes miai of the cut at c and connecting at e. Another use of this aji is the attachment at b, if white pushes though then black immediately cuts at c and white is short of liberties so either loses the corner or black gets to block white's push, turning it into a bad move. Thus white usually defends one point below c and black makes a thick connection to left left of b. Sometimes white doesn't defend straight away as then black may treat b lightly (e.g. jumping to f), so would keep attacking on the outside, and then black connects, white defends, and black runs.

Click Here To Show Diagram Code
[go]$$ Connect: good aji, bad points
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . 3 . . . . . . . . .
$$ | . 1 2 O . . . . . , .
$$ | a 4 6 . . O . . . . .
$$ | . 5 b . . . . . . . .
$$ | . . . . . . . . . . .
$$ ------------------------[/go]


If white connects, then black can no longer aim at a or b from the previous diagram, but instead has the connection at a. This is surprisingly big and is a difficult timing question. If white answers at b it does not make any eyes for black, but black may be pleased to get some sente yose.

Click Here To Show Diagram Code
[go]$$ Timing question
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . 3 . . . . . . . . .
$$ | . 1 2 O . . . . . , .
$$ | 7 4 6 . . O . . . . .
$$ | b 5 8 . . . . . . . .
$$ | . . a . . . . . . . .
$$ ------------------------[/go]


The important of white blocking at :w8: above can be seen in this game I am playing on OGS: http://www.online-go.com/games/board.php?boardID=291183 (lower left). After exchanging h4 for j5, I block in gote at c2 as I judged it was needed for the safety of my group, and also to weaken black. This was proved correct when black later made the surprisingly severe attack at h2, using the power of his ponnuki to the right. I only just managed to live, and this was because the descent to a threatens to make 1 eye (not 2 remember!) with the throw in at b.

If white ignores black's first line connection black can make one eye in gote in the corner and has some followups against white's shape for later: if white blocks :b7: at a then black b makes miai of c and d, so white usually has to answer :b7: at b, giving black some gain in yose and reduction of white's eyespace.

Click Here To Show Diagram Code
[go]$$ Ignore the connection
$$ | . . . . . . . . . . .
$$ | . . . . . . . 2 6 . .
$$ | . . . . . . . . . . .
$$ | . X . . . . . . . . .
$$ | . X O O d . . . . , .
$$ | 1 O O c b O . . . . .
$$ | . X 3 4 7 . . . . . .
$$ | . . 5 a . . . . . . .
$$ ------------------------[/go]


Even if white answers the clamp with the timid, safe connection instead of the greedy descent, it is not always a good exchange for black. This is a rather subtle point, but it makes black's 2 marked stones on the outside slightly heavier (harder to sacrifice). The reason for this is white has been strengthened so black has lost some other options. For example, say it is unplayed and later in the game black invades with the attachment as below. If white is strong around and wants to kill everything, :w2: is a strong move but as black has not clamped he can get :b7: in sente which helps a lot to make eyeshape.

Click Here To Show Diagram Code
[go]$$ Sabaki without clamp
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . # . . . . . . . . .
$$ | . # O O 4 6 . . . , .
$$ | . O . . 3 O 1 . 2 . .
$$ | . . 8 7 . 5 . . . . .
$$ | . . . . . . . . . . .
$$ ------------------------[/go]


If black has clamped and then later sacrificed the marked stones then :b7: is less sente as it only threatens to connect to the circled stone (which is not 100% alive) as opposed to cutting which is.

Click Here To Show Diagram Code
[go]$$ Sabaki with clamp slightly harder
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . # . . . . . . . . .
$$ | . # O O 4 6 . . . , .
$$ | . O O . 3 O 1 . 2 . .
$$ | . B . 7 . 5 . . . . .
$$ | . . . . . . . . . . .
$$ ------------------------[/go]


In conclusion, I would play the clamp in this position, but there is plenty to consider when doing so and it is far from automatically a good move. :)

Re: Araban vs Magicwand II

Posted: Tue Nov 29, 2011 2:35 pm
by Solomon
Click Here To Show Diagram Code
[go]$$Bcm61 Prisoners: white 2 black 0
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . X . . O . O . . . |
$$ | . X O O . . . . . . . . O O . O O X . |
$$ | . . X , O . . O . X . X . . O X X . . |
$$ | . X . . . . . O X . . . . X X . . X . |
$$ | . . . X . . . . X . . O . . O . . . . |
$$ | . . . . X . O . . . . . . . . X . . . |
$$ | . . O . . . . . X . . X . O . X . . . |
$$ | . . . . . . . . . X X O O . . . . . . |
$$ | . . . , . . . . . , O X . . . , . . . |
$$ | . . . O . . . . . . X X O O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 5 . . . . . . . . . . . . O . . . . |
$$ | . X O O . . . . . , . . O . O X X . . |
$$ | . . . . . O . . . . . . . O X . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Many players can probably relate with me when I say that I only considered two and only two moves here, either ascending or descending. Out of almost 300 possible places to play, I only considered 2. Now maybe it's not so bad that I don't even give 1 second of consideration for moves like A1, but how come is it that moves like

Click Here To Show Diagram Code
[go]$$Bc Prisoners: white 2 black 0
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . X . . O . O . . . |
$$ | . X O O . . . . . . . . O O . O O X . |
$$ | . . X , O . . O . X . X . . O X X . . |
$$ | . X . . . . . O X . . . . X X . . X . |
$$ | . . . X . . . . X . . O . . O . . . . |
$$ | . . . . X . O . . . . . . . . X . . . |
$$ | . . O . . . . . X . . X . O . X . . . |
$$ | . . . . . . . . . X X O O . . . . . . |
$$ | . . . , . . . . . , O X . . . , . . . |
$$ | . . . O . . . . . . X X O O . . . . . |
$$ | . . . e . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . 5 . . . . . . . . . . . . . . . . . |
$$ | . d . . . . . . . . . . . . O . . . . |
$$ | . X O O . . . . . , . . O . O X X . . |
$$ | b a . . . O . . . . . . . O X . . . . |
$$ | . c . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


also don't occur to me in the slightest, just as much as A1? Only after looking at it for some time can I provide a logical explanation that this move is not good. Simply, that 'a' becomes a higher profitable move for W as I lose endgames moves such as 'b' or getting to play 'c' had I played my original move instead. But I'd like to emphasize that this explanation only came about after I established that this :b5: is bad in my mind. What had me think negatively of this move instinctively in the first place? Simply that I haven't seen this move played before, either in my own or in professional games? That it just didn't "feel" right? I'm not sure.

What if a pro had told you this :b5: is the best move, and asked you to provide your explanation as to why it's a good move? Hmm...

"Because White has control in this area, it's important for Black to play lightly. Hence ascending or descending is too heavy here, and White must try to sabaki. :b5: is a great way to live on the side, while ensuring White doesn't eat the original move whole by playing 'd' either. Sure it lets White play 'a' scotch-free, but :b5: makes it easier for Black to run into the center. With tactics such as 'e', living will not be a problem at all. Also, the one-space jump is never bad."

So it's not hard to convince myself like this. And I think this is why it's so hard for me to improve - maybe a lot of the "only moves" to me aren't the only moves to consider after all. Maybe the logical explanations I play out in my head aren't so logical. Who knows, but one thing's for sure...I need sleep.

Re: Araban vs Magicwand II

Posted: Tue Nov 29, 2011 2:55 pm
by daniel_the_smith
@Araban

See my posts here, here, and especially here.

System 1 gave you just the two moves to consider. That process of coming up for reasons why you did or didn't consider other moves is, IMO, confabulation and/or rationalization. I think strong players do it frequently without realizing that the verbal reasons they give are not connected with or produced by the parts of the brain that actually generate the moves that they came up with. For this reason I trust the actual moves strong players produce a lot more than I trust their explanations for why the moves are good.

ETA:

On the other hand, really weak players--beginners--do a much larger amount of their decision making process with System 2, so their verbal reasons are more likely to actually be the reasons why they did what they did.

Strong players can give explanations that are accurate-- they sound like, "That move is bad because there's this ko <demonstrate>," or, "But then I'll kill your group like this <demonstrate>." I also trust things like, "that group is too weak <demonstrate 15 different ways its aji can be abused>." Also, strong players that have spent a lot of time trying might get good at teaching--which isn't the same skill as coming up with a strong move but will probably make their confabulations a little more accurate and a lot more helpful. :)

Re: Araban vs Magicwand II

Posted: Tue Nov 29, 2011 3:07 pm
by Magicwand
Click Here To Show Diagram Code
[go]$$Bcm61 Prisoners: white 2 black 0
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . X . . O . O . . . |
$$ | . X O O . . . . . . . . O O . O O X . |
$$ | . . X , O . . O . X . X . . O X X . . |
$$ | . X . . . . . O X . . . . X X . . X . |
$$ | . . . X . . . . X . . O . . O . . . . |
$$ | . . . . X . O . . . . . . . . X . . . |
$$ | . . O . . . . . X . . X . O . X . . . |
$$ | . . . . . . . . . X X O O . . . . . . |
$$ | . . . , . . . . . , O X . . . , . . . |
$$ | . . . O . . . . . . X X O O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X . . . . . . . . . . . . O . . . . |
$$ | . X O O . . . . . , . . O . O X X . . |
$$ | . 6 . . . O . . . . . . . O X . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Re: Araban vs Magicwand II

Posted: Tue Nov 29, 2011 3:32 pm
by Magicwand
i need to maintain point balalce~~
Click Here To Show Diagram Code
[go]$$Bcm61 this is what i had in mind.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . X . . O . O . . . |
$$ | . X O O . . . . . . . . O O . O O X . |
$$ | . . X , O . . O . X . X . . O X X . . |
$$ | . X . . . . . O X . . . . X X . . X . |
$$ | . . . X . . . . X . . O . . O . . . . |
$$ | . . . . X . O . . . . . . . . X . . . |
$$ | . . O . . . . . X . . X . O . X . . . |
$$ | . . . . . . . . . X X O O . . . . . . |
$$ | . . . , . . . . . , O X . . . , . . . |
$$ | . . . O . . . . . . X X O O . . . . . |
$$ | . 0 . . . . . . . . . . . . . . . . . |
$$ | . . 9 . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X . . . . . . . . . . . . O . . . . |
$$ | . X O O . . . . . , . . O . O X X . . |
$$ | . 6 8 . . O . . . . . . . O X . . . . |
$$ | . 7 . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Re: Araban vs Magicwand II

Posted: Tue Nov 29, 2011 3:51 pm
by Uberdude
Magicwand wrote:i need to maintain point balalce~~
Click Here To Show Diagram Code
[go]$$Bcm61 this is what i had in mind.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . X . . O . O . . . |
$$ | . X O O . . . . . . . . O O . O O X . |
$$ | . . X , O . . O . X . X . . O X X . . |
$$ | . X . . . . . O X . . . . X X . . X . |
$$ | . . . X . . . . X . . O . . O . . . . |
$$ | . . . . X . O . . . . . . . . X . . . |
$$ | . . O . . . . . X . . X . O . X . . . |
$$ | . . . . . . . . . X X O O . . . . . . |
$$ | . . . , . . . . . , O X . . . , . . . |
$$ | . . . O . . . . . . X X O O . . . . . |
$$ | . 0 . . . . . . . . . . . . . . . . . |
$$ | . . 9 . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X . . . . . . . . . . . . O . . . . |
$$ | . X O O . . . . . , . . O . O X X . . |
$$ | . 6 8 . . O . . . . . . . O X . . . . |
$$ | . 7 . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Rather than black 69 here, I would seriously consider the rather unusual "armpit hit" as below. This move is a favourite of Kobayashi Koichi and aims to settle quickly. It not only makes more eyespace for black, but white's group on the side ends up without definite eyespace either (though it is thick) so in the future black can even consider gently attacking white (note the marked white stone ends up poorly placed, it should be 1 lower) and can aim at a. Maybe white can resist strongly for 76 though.

Click Here To Show Diagram Code
[go]$$Bcm69 My plan as black.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . X . . O . O . . . |
$$ | . X O O . . . . . . . . O O . O O X . |
$$ | . . X , O . . O . X . X . . O X X . . |
$$ | . X . . . . . O X . . . . X X . . X . |
$$ | . . . X . . . . X . . O . . O . . . . |
$$ | . . . . X . O . . . . . . . . X . . . |
$$ | . . W . . . . . X . . X . O . X . . . |
$$ | . a . . . . . . . X X O O . . . . . . |
$$ | . 6 . , . . . . . , O X . . . , . . . |
$$ | . 5 2 O 8 . . . . . X X O O . . . . . |
$$ | . 7 1 3 4 . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . 9 . . . . . . . . . . . . . . . |
$$ | . X . . . . . . . . . . . . O . . . . |
$$ | . X O O . . . . . , . . O . O X X . . |
$$ | . O O . . O . . . . . . . O X . . . . |
$$ | . X . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


I wonder if Araban will find this move given his previous post about considering unusual moves, I think it's hard to find if you don't know it.

Re: Araban vs Magicwand II

Posted: Tue Nov 29, 2011 8:21 pm
by RedStick
Uberdude wrote:
Tooveli wrote:Re: 67

Click Here To Show Diagram Code
[go]$$Bcm61 Prisoners: white 2 black 0
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . X . . O . O . . . |
$$ | . X O O . . . . . . . . O O . O O X . |
$$ | . . X , O . . O . X . X . . O X X . . |
$$ | . X . . . . . O X . . . . X X . . X . |
$$ | . . . X . . . . X . . O . . O . . . . |
$$ | . . . . X . O . . . . . . . . X . . . |
$$ | . . Q . . . . . X . . X . O . X . . . |
$$ | . . . . . . . . . X X O O . . . . . . |
$$ | . . . , . . . . . , O X . . . , . . . |
$$ | . . . Q . . . . . . X X O O . . . . . |
$$ | . . . . . . . . . . . a . . . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 5 . . . . . . . . . . . . O . . . . |
$$ | . X 4 O . . . . . , . . O . O X X . . |
$$ | a 6 8 . . O . b . . . . . O X . . . . |
$$ | . 7 . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I was taught 67 as joseki. It's meant to be a good probe and good timing in this sequence.
It is hard for White to descend at a because of the weaknesses it creates (eg. Black plays at b). Forcing White to play 68 early leaves connecting underneath in the corner as big endgame for later.


Yes, the 67 clamp probe is standard (it is played immediately in about 300 of 500 games in GoGoD with this corner shape), but it is not always a good move according to Guo Juan. The point is it asks white whether he wants to connect or descend.

Actually white has a 3rd choice, tenuki, say to play a pincer on the left side, forcing black to capture the stone and make eyes and corner profit so black would usually be content with this; if he is not (e.g. because the white pincer makes some huge left side then he should extend down the side first as the clamp is his privilege: white would usually make a kick/block/checking extension to stop black extending further down the side, and then black could clamp.

Click Here To Show Diagram Code
[go]$$ Descent: good points, bad aji
$$ | . . . . . . . . . . .
$$ | . . . f . . . . . . .
$$ | . . . . . . . . . . .
$$ | . 3 . b . . . . . . .
$$ | . 1 2 O . . . . . , .
$$ | 6 4 c . . O . a . . .
$$ | . 5 . d . e . . . . .
$$ | . . . . . . . . . . .
$$ ------------------------[/go]


If white descends then black loses yose (in yose black could exchange 6 for 5), in exchange for white having bad aji from the cut left at c. As others mentioned, one use of this aji is the point a, if white makes a pincer on it then black has the placement at d which makes miai of the cut at c and connecting at e. Another use of this aji is the attachment at b, if white pushes though then black immediately cuts at c and white is short of liberties so either loses the corner or black gets to block white's push, turning it into a bad move. Thus white usually defends one point below c and black makes a thick connection to left left of b. Sometimes white doesn't defend straight away as then black may treat b lightly (e.g. jumping to f), so would keep attacking on the outside, and then black connects, white defends, and black runs.

Click Here To Show Diagram Code
[go]$$ Connect: good aji, bad points
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . 3 . . . . . . . . .
$$ | . 1 2 O . . . . . , .
$$ | a 4 6 . . O . . . . .
$$ | . 5 b . . . . . . . .
$$ | . . . . . . . . . . .
$$ ------------------------[/go]


If white connects, then black can no longer aim at a or b from the previous diagram, but instead has the connection at a. This is surprisingly big and is a difficult timing question. If white answers at b it does not make any eyes for black, but black may be pleased to get some sente yose.

Click Here To Show Diagram Code
[go]$$ Timing question
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . 3 . . . . . . . . .
$$ | . 1 2 O . . . . . , .
$$ | 7 4 6 . . O . . . . .
$$ | b 5 8 . . . . . . . .
$$ | . . a . . . . . . . .
$$ ------------------------[/go]


The important of white blocking at :w8: above can be seen in this game I am playing on OGS: http://www.online-go.com/games/board.php?boardID=291183 (lower left). After exchanging h4 for j5, I block in gote at c2 as I judged it was needed for the safety of my group, and also to weaken black. This was proved correct when black later made the surprisingly severe attack at h2, using the power of his ponnuki to the right. I only just managed to live, and this was because the descent to a threatens to make 1 eye (not 2 remember!) with the throw in at b.

If white ignores black's first line connection black can make one eye in gote in the corner and has some followups against white's shape for later: if white blocks :b7: at a then black b makes miai of c and d, so white usually has to answer :b7: at b, giving black some gain in yose and reduction of white's eyespace.

Click Here To Show Diagram Code
[go]$$ Ignore the connection
$$ | . . . . . . . . . . .
$$ | . . . . . . . 2 6 . .
$$ | . . . . . . . . . . .
$$ | . X . . . . . . . . .
$$ | . X O O d . . . . , .
$$ | 1 O O c b O . . . . .
$$ | . X 3 4 7 . . . . . .
$$ | . . 5 a . . . . . . .
$$ ------------------------[/go]


Even if white answers the clamp with the timid, safe connection instead of the greedy descent, it is not always a good exchange for black. This is a rather subtle point, but it makes black's 2 marked stones on the outside slightly heavier (harder to sacrifice). The reason for this is white has been strengthened so black has lost some other options. For example, say it is unplayed and later in the game black invades with the attachment as below. If white is strong around and wants to kill everything, :w2: is a strong move but as black has not clamped he can get :b7: in sente which helps a lot to make eyeshape.

Click Here To Show Diagram Code
[go]$$ Sabaki without clamp
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . # . . . . . . . . .
$$ | . # O O 4 6 . . . , .
$$ | . O . . 3 O 1 . 2 . .
$$ | . . 8 7 . 5 . . . . .
$$ | . . . . . . . . . . .
$$ ------------------------[/go]


If black has clamped and then later sacrificed the marked stones then :b7: is less sente as it only threatens to connect to the circled stone (which is not 100% alive) as opposed to cutting which is.

Click Here To Show Diagram Code
[go]$$ Sabaki with clamp slightly harder
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . # . . . . . . . . .
$$ | . # O O 4 6 . . . , .
$$ | . O O . 3 O 1 . 2 . .
$$ | . B . 7 . 5 . . . . .
$$ | . . . . . . . . . . .
$$ ------------------------[/go]


In conclusion, I would play the clamp in this position, but there is plenty to consider when doing so and it is far from automatically a good move. :)


Uberdude, this is an incredibly helpful post. I have seen but never quite understood these moves. Many thanks.

Re: Araban vs Magicwand II

Posted: Wed Nov 30, 2011 7:35 am
by hyperpape
Yeah, really good post. Worth a link on sensei's for now (http://senseis.xmp.net/?4463Enclosure24Approach), and some integration when I have a chance.

Re: Araban vs Magicwand II

Posted: Wed Nov 30, 2011 11:03 pm
by Solomon
Click Here To Show Diagram Code
[go]$$Bcm61 Prisoners: white 2 black 0
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . X . . O . O . . . |
$$ | . X O O . . . . . . . . O O . O O X . |
$$ | . . X , O . . O . X . X . . O X X . . |
$$ | . X . . . . . O X . . . . X X . . X . |
$$ | . . . X . . . . X . . O . . O . . . . |
$$ | . . . . X . O . . . . . . . . X . . . |
$$ | . . O . . . . . X . . X . O . X . . . |
$$ | . . . . . . . . . X X O O . . . . . . |
$$ | . . . , . . . . . , O X . . . , . . . |
$$ | . . . O . . . . . . X X O O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X . . . . . . . . . . . . O . . . . |
$$ | . X O O . . . . . , . . O . O X X . . |
$$ | . O . . . O . . . . . . . O X . . . . |
$$ | . 7 . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Click Here To Show Diagram Code
[go]$$Bcm61 Prisoners: white 2 black 0
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . X . . O . O . . . |
$$ | . X O O . . . . . . . . O O . O O X . |
$$ | . . X , O . . O . X . X . . O X X . . |
$$ | . X . . . . . O X . . . . X X . . X . |
$$ | . . . X . . . . X . . O . . O . . . . |
$$ | . . . . X . O . . . . . . . . X . . . |
$$ | . . O . . . . . X . . X . O . X . . . |
$$ | . . . . . . . . . X X O O . . . . . . |
$$ | . . . , . . . . . , O X . . . , . . . |
$$ | . . . O . . . . . . X X O O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X . . . . . . . . . . . . O . . . . |
$$ | . X O O . . . . . , . . O . O X X . . |
$$ | a O b . . O c . . . . . . O X . . . . |
$$ | . X . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

This is a probe to see whether White will respond at 'a' or 'b'. If he plays 'a', moves like 'c' will be a thorn to his side as he will always need to keep the cut at 'b' in check. But if he plays 'b', then of course it saves me the endgame move of 'a' later. If I was White....weighing the pros and the cons, I'd probably play 'b'. The big question is how I need to handle the two stones after he makes his choice. I've got ideas, but the double-edged sword of a Malkovich game is that it allows you to postpone these kinds of thoughts and mainly focus on the current state. In a timed game, I would have already decided.

Re: Araban vs Magicwand II

Posted: Thu Dec 01, 2011 9:25 am
by Magicwand
Click Here To Show Diagram Code
[go]$$Bcm61 Prisoners: white 2 black 0
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . X . . O . O . . . |
$$ | . X O O . . . . . . . . O O . O O X . |
$$ | . . X , O . . O . X . X . . O X X . . |
$$ | . X . . . . . O X . . . . X X . . X . |
$$ | . . . X . . . . X . . O . . O . . . . |
$$ | . . . . X . O . . . . . . . . X . . . |
$$ | . . O . . . . . X . . X . O . X . . . |
$$ | . . . . . . . . . X X O O . . . . . . |
$$ | . . . , . . . . . , O X . . . , . . . |
$$ | . . . O . . . . . . X X O O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X . . . . . . . . . . . . O . . . . |
$$ | . X O O . . . . . , . . O . O X X . . |
$$ | . O 8 . . O . . . . . . . O X . . . . |
$$ | . X . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Re: Araban vs Magicwand II

Posted: Fri Dec 02, 2011 5:38 am
by SpongeBob
@Araban:
Araban wrote:I've got ideas, but the double-edged sword of a Malkovich game is that it allows you to postpone these kinds of thoughts and mainly focus on the current state. In a timed game, I would have already decided.

Could you explain this difference?