Life In 19x19

Dusk Eagle wrote:Hey Alguien,

Just as a rule of thumb, try to avoid playing moves like the one below (of course there are exceptions). The extra power you give black is far greater than the extra stability such a stone provides. When you want to play an extension when there's a pincer, the correct location is one space farther from the pincer ('a').

Thank you.

I'll reply on the study group sub-forum.

EdLee wrote:

Alguien wrote:That seems to give a worse result than e16...

Remember that E16 is an empty triangle, and pushing W from behind.

True, but it gives a better result. Don't let proverbs stop you playing good moves. If you want to pick a different proverb to justify it, it is double sente and creates an important cutting point in white's shape that he has to spend a move to defend (or face a very hard fight).

Compare these two results:

Click Here To Show Diagram Code

[go]$$Bcm11
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . b . . . . . . . . . . . . . |
$$ | . . . . X O . . . . . . . . . . . . . |
$$ | . . X X X O . . . X . . . . . X . . . |
$$ | . . X O . O . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . a . . . W . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

Click Here To Show Diagram Code

[go]$$Bcm11
$$ -----------------------
$$ | . . . . . . . . . . .
$$ | . . . . . b . . . . .
$$ | . X X X X O . . . . .
$$ | X . . X O O . . . X .
$$ | . X X O . . . . . . .
$$ | . O X O . a . . . . .
$$ | . . O W . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .[/go]

In both of them black has sente. In the first black's corner is not sealed in: he can jump to a next and this indeed quite common as his next move: it's very big to avoid getting sealed in, makes some points, stops the white wall getting a base and develop on the side there by blocking at c14 (which would also make the descent at b white's sente which could help with fighting on the top side). In the second black's corner is a few points bigger but he is sealed in. White's outside wall is stronger, though black does have the shape point of a to aim at (if white dislikes this the d13 connection could be f13, but that is weaker on the side), and not only does he have centre influence he has influence and thus potential on the left side. As a plus for black his capture shape is very strong so the descent at b is just yose and doesn't have any life and death implications.

I have got the second result as white many many times in handicap games. I don't remember anyone ever playing the good empty triangle of the first one. Once people stop blindly following proverbs it'll be harder to win handicap games .

(As an aside, another example of a good empty triangle people often avoid that crops up in handicap games is below, often they jump to a to avoid an empty triangle but then black can push and block on the 2nd line in sente (and spot the L group in the making!):

Click Here To Show Diagram Code

[go]$$Wc
$$ -------------------
$$ | . . . . . . . . .
$$ | . . . a . . . . .
$$ | . . . 4 3 . . . .
$$ | . . 2 X . . . . .
$$ | . . . . . . . . .
$$ | . . 1 . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

As Bill said, the location of the initial pincer on the top side is relevant. The 2 space high pincer is perhaps more common as the attacking shape, and then after the result of the first diagram it is closer to the white wall. This could make the white wall a bit weaker as it has less space for eyes, but conversely it means the black stone is also closer to thickness so a counter pincer against it for white is likely to go better. I've heard Go Seigen liked this kick and 2 space pincer for black. It's a sort of having you cake and eating it idea as normally if you pincer they can jump to 3-3 but now you get a pincer and the corner. In exchange white gets a sort-of thick group with a chance to counter pincer, but if the whole board position has some support that means you welcome the counter pincer fight (and can even pretend to attack the wall a bit) then it can be an interesting way to play. Maybe with a little hint of overplay, but that's Go Seigen's style.

In summary, the empty triangle is good, crawling is not. Locally speaking black gets greater profit but white has thickness and looks forward to a counter pincer on the top side or blocking on the left, but it's black's choice which one white can do, so if one of these is not so great for white given the whole board position it's a nice active way for black to play.