Life In 19x19

Schachus's question reminded me of one that came up for me in the following position:

Click Here To Show Diagram Code

[go]$$Bc
$$ --------------------
$$ , . . . . . , . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . X . . |
$$ . . . . . . . . . . |
$$ . . . . . . . O . . |
$$ . . . . . . . X X . |
$$ , . . . B X X X O . |
$$ . . . . O . O O O . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ --------------------[/go]

The marked black stone is not joseki. Why? As Bill stressed in his comments, it is sente. White has to extend because being boxed in would be problematic. The only thing I can come up with is that considering only the local position, the additional influence for black is not worth the additional points white takes with the extension. But at my level, I have a hard time making these assessments.

Click Here To Show Diagram Code

[go]$$B
$$ . . . . . . . . . . |
$$ . . . . . . . X . . |
$$ . . . . . . . . . . |
$$ . . . . . . . O . . |
$$ . . . . . . . X X . |
$$ , . . . B X X X O . |
$$ . . . . O . O O O . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$----------------------[/go]

BlindGroup wrote:White has to extend because being boxed in would be problematic.

Hi BlindGroup,

A few things to ponder.

BlindGroup wrote:

$$Bc
$$ --------------------
$$ , . . . . . , . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . X . . |
$$ . . . . . . . . . . |
$$ . . . . . . . O . . |
$$ . . . a . . . X X . |
$$ , . . . B X X X O . |
$$ . . . . O . O O O . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ --------------------

Click Here To Show Diagram Code

[go]$$Bc
$$ --------------------
$$ , . . . . . , . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . X . . |
$$ . . . . . . . . . . |
$$ . . . . . . . O . . |
$$ . . . a . . . X X . |
$$ , . . . B X X X O . |
$$ . . . . O . O O O . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ --------------------[/go]

The marked black stone is not joseki.

Careful with that. Whilst the joseki finishes with white jumping out on the 3rd line and then black usually tenukis, pushing there is a reasonably common post-joseki follow-up, so don't delete it from your Go vocabulary (but think who the exchanges help more before playing them, as one always should). It is thicker than the knight's move at a and black will usually continue pushing, e.g. http://ps.waltheri.net/database/game/46312/ In that game you can also see Lee Changho do the kick we are often told not to do at the bottom left beforehand. This, along with the pushing, is part of his strategy to force black to take the lower side territory in a not so efficient manner: the pushing is basically a double sente move.

So you want to know how to evaluate the rasult after the tenuki to the black push, this one:

Click Here To Show Diagram Code

[go]$$W :w1: tenuki
$$ . . . . . . . . . . |
$$ . . . . . . . X . . |
$$ . . . . . . . . . . |
$$ . . . . . . . O . . |
$$ . . . . . . . X X . |
$$ , . . . X X X X O . |
$$ . . . 6 O 2 O O O . |
$$ . . . . 4 3 5 . . . |
$$ . . . . . . . . . . |
$$----------------------[/go]

. THis is a position, where locally black has played two more stones(white tenuki for 1 and again for 7).
We can compare it to another position, where black has two more stones, which is the joseki invasion to the ogeima that also ends in the L+2 group:

Click Here To Show Diagram Code

[go]$$W
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ , . . . . 7 X 2 9 . |
$$ . . . X 8 4 3 1 . . |
$$ . . . . 6 5 . . . . |
$$ . . . . . . . . . . |
$$----------------------[/go]

continuation

Click Here To Show Diagram Code

[go]$$B
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . . . 3 . . |
$$ . . . . . 5 . . 1 . |
$$ , . . . . Q X X O . |
$$ . . . X X X O O 2 . |
$$ . . . . X O 4 . . . |
$$ . . . . . . . . . . |
$$----------------------[/go]

white ends in sente, so also here black has locally played two more stones, so we can compare the two positions(This is very important: One move is worth a lot, so make sure to compare positions with the same move tally(or count the difference in moves in when you make the judgement)). The corner is oviously the same. I would argue that the black outside is a little better in the first one, because:

-the ponnuki makes the fist one essentially alive
-the first one already has an extension to the top side
-the triangled white stone has some aji in the second one(though not a lot), while there is no cutting aji in the first one.

Thus with white you seem to be a little worse off, then you "should be" for having a corner where you are inside and your opponent has two more stones.
Actually there is one more thing to consider. In the first case, it was blacks corner, white approached and the white tenuki came later in the sequence. In the second case, black had a corner with 2 moves to start with, so the white tenuki was very early and thus presumably worth a little more.
Also in the second sequence, the white invasion is something that might be considered bad if it were done immediately, it is more for later. So in order to be satisfied with the tenuki in the other case, I would like it to be a little better than tis invasion vartiation.
There is also one thing that goes the other way, though: the ogeima enclosure from 4-4 is a little uncommon precisely because you can stilll steal the corner so easily. Hence maybe white got a little more than would be "even" because of the uncommon enclosure, that emphazised the outside.

I hope this way of thinking helps you.

EdLee wrote:These are a few reasons that the joseki stops...

Thank you Ed. This is exactly what I was wondering.

Schachus wrote:We can compare it to another position, where black has two more stones, which is the joseki invasion to the ogeima that also ends in the L+2 group.

This is an interesting point. More generally, I like your approach to this and the J+1/L+2 question of looking for isomorphisms between the different positions. That seems like a very useful learning technique!

uberdude wrote:In that game you can also see Lee Changho do the kick we are often told not to do at the bottom left beforehand. This, along with the pushing, is part of his strategy to force black to take the lower side territory in a not so efficient manner: the pushing is basically a double sente move.

Good example. I agree that the kick was surprising, but before that, I was surprised by move 24:

Click Here To Show Diagram Code

[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X X O . . . . O . . . X . . . . |
$$ | . . X , O . O . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . W . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . O O . |
$$ | . . . O . . . . . , . . . . O O O X . |
$$ | . . . . . . . . . . . . . X . X X X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

This seems to violate the general principle of prioritizing the corners over side extensions. Ex post, this seemed like the strategically key move in the fuseki that allowed white to create the double-moyo threat. Was this clearly a good move at the time? Unless I'm over interpreting, it seemed like black recognized this as well with the short, high extension from from the two-stone wall fallowing the kick -- which if right might have even been the motivation for white's incentive for giving him the boot in the first place.

BlindGroup wrote: I agree that the kick was surprising, but before that, I was surprised by move 24:

$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X X O . . . . O . . . X . . . . |
$$ | . . X , O . O . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . W . . |
$$ | . . . , . . . . . , . . . . . , a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . O O . |
$$ | . . . O . . . . . , . . . . O O O X . |
$$ | . . . . . . . . . . . . . X . X X X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X X O . . . . O . . . X . . . . |
$$ | . . X , O . O . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . W . . |
$$ | . . . , . . . . . , . . . . . , a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . O O . |
$$ | . . . O . . . . . , . . . . O O O X . |
$$ | . . . . . . . . . . . . . X . X X X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

This seems to violate the general principle of prioritizing the corners over side extensions. Ex post, this seemed like the strategically key move in the fuseki that allowed white to create the double-moyo threat. Was this clearly a good move at the time? Unless I'm over interpreting, it seemed like black recognized this as well with the short, high extension from from the two-stone wall fallowing the kick -- which if right might have even been the motivation for white's incentive for giving him the boot in the first place.

That move 24 was a favourite move of Lee Changho that fits well with his style: it stabilizes the white group and prevents black's good extension at a which develops from the shimari and aims at attacking the white wall. As the only unapproached corner was a 4-4 adding a move there is not so urgent compared to if it were a 3-4 (though making shimari from 4-4 is common these days).

One reason for the short extension is black doesn't like the following sequence in which white invades and immediately sacrifices in order to secure the corner against a 3-3 invasion (this was another of Lee's favourite tactics). White would then probably continue at a as in the game (black might resist and not defend at 7, or fight with 3).

Click Here To Show Diagram Code

[go]$$B
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X X O . . . . O . . . X . . . . |
$$ | . . X , O . O . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . O O . |
$$ | . . . O . X . 3 . 1 . . . a O O O X . |
$$ | . . . . O X 7 2 . . . . . X . X X X . |
$$ | . . . . 6 4 5 . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

So black plays the closer extension to avoid this sort of over-concentration. In fact Lee Sedol did the same thing in his 2nd game with AlphaGo, which then led to AlphaGo's famous shoulder hit from the 5th line to cause over-concentration from the other side!

I have been very delinquent in updating this, but I have a lot to update!

I'll update my goals and study effort soon, but first I've achieved the following:

1. I finally achieved my goal of breaking into the SDK world on IGS with a rank of 9k. Not sure how long I'll be able to keep it, but one step at a time.

2. I finally settled down to a rank of 7k on KGS. I'm not too far away from 6k, though. So, I'm aiming to get there in a month or so. I've been playing more on KGS lately than IGS because the style of play on KGS is new to me, and I'm trying to get used to it.

3. I haven't been able to play in-person games as frequently as I had hoped, but I've gone to a few local club meetings. I'm still trying to get used to the different perspective on has on the board when you play in person. Standing helps a bit, but it's still different!

4. I played in my first in-person go tournament a couple weekends ago. Based on my KGS and IGS ranking and the conversion chart on Sensei's Library, I entered my rank as 6k, and that seems to be about right. I lost my first game to a very bright 6k tween. He played very well. He probably would have beaten me regardless, but I helped him along. For some reason, I just couldn't settle down and focus. However, things fell into shape after that and I won my next three games. I was fairly happy with games two and three, but game four was a mess. I won, but I shouldn't have. I played a 4k opponent in an even game, and it seemed like the game came down to whether or not one of my groups could escape to safety. Eventually, my opponent resigned because he thought I had escaped. I thought the same, but afterwards, it became clear that we were both wrong. That said, it was a long day. So, not too surprising that we might make such a mistake.

I ended up at 5k once AGA crunched the numbers, but I'm guessing this is largely driven by my fourth game. So, I expect to settle down at 6k for now.

I played the following game on KGS today. I was ahead early on, but then made a series of mistakes to give the game away. This is a frequent cause of my losses, and I'm working to figure out how to correct it. In this game, I simply misread something at the very end, but that's happening less often. I think what I need to work on is to recognize when I'm ahead and then figure out how to simplify the game to avoid problems. I'm very bad at judging when I'm up in a game.

Anyway, my analysis is below. The only move about which I don't have a firm opinion is move 73:

Click Here To Show Diagram Code

[go]$$
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . X . . . . . X X X X O X O O O O |
$$ | . . O . . X . X X O O X O O X X X X . |
$$ | . . . O . . . X O O X O . O . X . . . |
$$ | . . . . . . X O . O X O O O . . . . . |
$$ | . . . O . . X O . O X X X X X . . . . |
$$ | . . . . . X O . O . . . . . . . . . . |
$$ | . . . . . X O . O X . . . . . . X . . |
$$ | . . . . . . . . . X . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . O . O . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . O , . O . . . X . O . |
$$ | . . B . . X . . . . . . . X . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

I expected the pincer after playing the approach (although I was expecting J3 rather then J4). I also considered jumping up and a double approach. My move gives white the start of a moyo, but with the stones in the bottom center on the fourth line, I feel like I have options to deal with it.

Here is the full game:

30 second 4k opinion: I like 73@C3, but I don't like 83@N5. You're not so strong on the bottom yourself and you don't have the correct local support to push and cut.

My blitz move for 83 is M2, giving yourself a bigger base and making White overconcentrated if he defends his territory on the left. (If he doesn't, you could end up reducing it to almost nothing, especially with ideas like F2.)

dfan wrote:30 second 4k opinion: I like 73@C3, but I don't like 83@N5. You're not so strong on the bottom yourself and you don't have the correct local support to push and cut.

My blitz move for 83 is M2, giving yourself a bigger base and making White overconcentrated if he defends his territory on the left. (If he doesn't, you could end up reducing it to almost nothing, especially with ideas like F2.)

Thanks. I didn't realize that this group was that weak. And this is also consistent with the comment you made to my
last post. Looks like I generally need to be more careful about buttressing these weak groups, or at least recognizing when they are weak!

After allowing my opponent to live unconditionally -- yet again -- within the 4-4 small knight enclosure, I decided to do a deep dive on the invasion variations.

The following sgf provides the results:



I've included every variation that I've seen, but I'm sure that I'm still missing a few.

And in case anyone finds this useful, I also put together a series of sgf files that can be loaded into the Easy Go app to practice these sequences: https://lifein19x19.com/download/file.php?id=8524

References: The information that I have used to create this can be found in a wide range of sources, but I used Chikun's All About Life and Death (above) to double check my assessment of the status of some of the groups. I also have provided the relevant links for the standard groups (L, L+1, J+1) in the main SGF to Sensei's Library.

There seems to be a severe mistake in your line called "SGF 7". I added some comments there and on the line "sgf 1"

Schachus wrote:There seems to be a severe mistake in your line called "SGF 7". I added some comments there and on the line "sgf 1"

Thank you! Both for the correction and taking the time to even look. Let update the file in the original post to make the correction.

Despite clear mistakes, I feel like I played better than normal in this game. So, I thought I'd put it in my journal.

Hi BlindGroup,

This helps W fix his shape: W leans at Q12.
Probably the shared vital point is Q12.

Q12.