Life In 19x19

Posted: **Sun Aug 26, 2018 9:46 am**

ez4u wrote:The lower left is dead if White cuts at D2, so better shift this to the "did poorly" list?

Bill Spight wrote:Second Dave.

Oy vey... Good to know. But painful to hear...

I've been meaning to spend some time with this shape, and I clearly need to do so. Bill, thanks for your extensive list of sequences. That is extremely helpful.

I think I'm starting to see the value of the third push at G2. I was aware of that move, but had gotten away with not playing it so many times that I didn't understand it's value.

Click Here To Show Diagram Code: [go]$$c $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . , . . . . . X . . . | $$ | . . X X O O O . . . . . . . . . . . . | $$ | . . . . X X B . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Posted: **Thu Sep 13, 2018 6:51 pm**

Would someone have time to take a gander at this game?

So, I won 4 games of 5 on my new provisional 4k account on IGS, and they bumped me to a provisional 3k. Wasn't sure that this was going to go well, but it seemed to go quite smoothly. Looking back at it, I can identify a number of mistakes on my part, but my opponent made just a few more...

I'm particularly interested in thoughts about the play on the lower left. I feel like I dodged a major bullet when black chose the wrong direction for

.

was clearly a mistake. Howver, I can't figure out how to take advantage of black's weakness while not allowing him to create a wall with

at B8.

Posted: **Thu Sep 13, 2018 7:32 pm**

The lower left?

How about a cut at B-07?

Posted: **Fri Sep 14, 2018 9:27 am**

Bill Spight wrote:The lower left?

How about a cut at B-07?

I see! I think that answers my question on

as well, but I don't understand the rationale.

At

, I played the marked move at K4, but you think I should have played A:

Click Here To Show Diagram Code: [go]$$c $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . O . . . O X X . . . | $$ | . . . , . . . . . , . . . O O , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . a X . . . . . . . . . . . . . . . . | $$ | . X Q Q . . . . . . . . . . . . d . . | $$ | . . X Q . . . . . . . . . . . . . . . | $$ | . . X Q . . . . . W b c . B . O . . . | $$ | . . X Q . . . . . . . . . . . . . . . | $$ | . . Q . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

At the point that black tenukied with

to play the marked black stone, I knew that the best local follow-up was at A. What I couldn't figure out was the timing. I didn't play it until

, and by that time, it would have been a very different game if black had chosen the outside instead of living in the corner.

My reasoning for

was that (a.) the marked stones are too weak to survive without a base and (b.) the pincer that I played is both a reply to the corner approach and a very reasonable extension from the marked stones. Looking back, I think that both of these statements are correct, but what I missed is that A would also give my marked stones a base.

Having said that though, I still don't see why A is the obvious move. It seems that A and the extension being miai argues against both my move and A for

. For example, I could play a tighter pincer like B or C. In fact, just falling back to D now looks most attractive to me. Following D, I'd retain sente if black decided to settle and if black opted instead to continue on the left, the pincer at b or c would work well with the marked stones. Plus, those marked stones can push upwards in sente.

What am I missing here... I'm guessing that A has value beyond providing a base for my marked stones, but I can't see it.

Posted: **Fri Sep 14, 2018 3:39 pm**

Bill Spight wrote:The lower left?

How about a cut at B-07?

After getting home form work, I finally had time to run the game through Lizzie. Here is what Lizzie seems to prefer:

Click Here To Show Diagram Code: [go]$$Wc $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . O . . . O X X . . . | $$ | . . . , . . . . . , . . . O O , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . 0 . . . . . . . . . . . . . . | $$ | . . X 8 9 . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . 7 . . . | $$ | . 4 X O . . . . . . . . . . . . . . . | $$ | 3 2 X O . . . . . 5 . . . B . O . . . | $$ | . 1 X O . . . . . . . a . . . . . . . | $$ | . 6 O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Her second choice for

is either the low one-space pincer at A or 7. However, all of these moves, including the cut at B7 and my game move, are within 2-3 percent of each other with my move being the worst.

That said, Bill, it would still be useful to know what you were thinking.

Posted: **Fri Sep 14, 2018 4:19 pm**

BlindGroup wrote:What am I missing here... I'm guessing that A has value beyond providing a base for my marked stones, but I can't see it.

What is the sequence of moves you think would follow after a?

Posted: **Fri Sep 14, 2018 4:37 pm**

Click Here To Show Diagram Code: [go]$$W $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . O . . . O X X . . . | $$ | . . . , . . . . . , . . . O O , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | . . X O . . . . . . . . . . . . . . . | $$ | . . X O . . . . . . . . . X . O . . . | $$ | . . X O . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

the marked stones are too weak to survive without a base

Posted: **Fri Sep 14, 2018 4:51 pm**

Thanks for showing Leela Zero's ideas.

What was I thinking?

For starters, here is a joseki that is still around, but not the most popular.

Click Here To Show Diagram Code: [go]$$Bc Joseki $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . O . . . O X X . . . | $$ | . . . , . . . . . , . . . O O , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . 6 7 . . . . . . . . . . . . . . . . | $$ | . 5 4 8 . . . . . . . . . . . . . . . | $$ | . . 3 O . . . . . , . . . . . O . . . | $$ | . . 1 2 . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Click Here To Show Diagram Code: [go]$$Bcm9 Joseki (continued) $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . O . . . O X X . . . | $$ | . . . , . . . . . , . . . O O , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . 1 . . . . . . . . . . . . . . . . . | $$ | 3 O X . . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | . 2 X O . . . . . , . . . . . O . . . | $$ | . 4 X O . . . . . . . . . . . . . . . | $$ | . 6 5 . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

The joseki goes up to

, and usually continues with

and

now or later, because of the aji for Black.

Compare that with this.

Click Here To Show Diagram Code: [go]$$Wc Other $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . O . . . O X X . . . | $$ | . . . , . . . . . , . . . O O , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . 2 . . . . . . . . . . . . . . . . . | $$ | 4 1 X . . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | . 3 X O . . . . . . . . . . . . . . . | $$ | . . X O . . . . . , . . . X . O . . . | $$ | . 5 X O . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

follows the proverb to capture the cutting stone. (Not that the bots or humans always follow it.

) Compared with the joseki, Black may be a little better, because the Black stones are one line closer to the Black top left corner, but White is a good bit better, with a bigger corner, a bigger wall, and no Black aji. So I figured Black would not like that. (In the variation you show White also threatens to take the corner and Black resists.)

Click Here To Show Diagram Code: [go]$$Wc Other $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . O . . . O X X . . . | $$ | . . . , . . . . . , . . . O O , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 3 . . . . . . . . . . . . . . . . | $$ | . 1 X . . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | 2 . X O . . . . . . . . . . . . . . . | $$ | . . X O . . . . . , . . . X . O . . . | $$ | . . X O . . . . . . . . . . . . . . . | $$ | . 4 O a . . . . . . . . . . . . . . . | $$ | . b . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

I think that Wa is sente later, threatening a ko in the corner, starting with "b" if Black does not reply. I like the wraparound wall.

Note that in this variation White keeps sente.

Posted: **Fri Sep 14, 2018 7:13 pm**

It is probably also worth considering the cut inside, in order to take the outside:

Click Here To Show Diagram Code: [go]$$W $$ | . . . . . . $$ | . . 5 . . . $$ | . 3 X . . . $$ | . X O O . . $$ | 4 1 X O . . $$ | . 2 X O . . $$ | . . X O . . $$ | . a O . . . $$ | . . . . . . $$ +------------[/go]

I feel like whenever I see this sort of problem, the official solution (as determined by pros or their ghostwriters) is to cut inside and take the outside, rather than vice versa, but I'm not strong enough to be confident that it is really best.

I am starting to develop an appreciation for this sort of ridiculous thickness, though. One extra thing it has going for it in this particular situation is that Black needs to play at a immediately just to live.

Anyway, all of this helps explain why in practice Black generally responds to the hane with a immediately.

Posted: **Tue Sep 18, 2018 7:58 pm**

dfan wrote:It is probably also worth considering the cut inside, in order to take the outside:

$$W
$$ | . . . . . .
$$ | . . 5 . . .
$$ | . 3 X . . .
$$ | . X O O . .
$$ | 4 1 X O . .
$$ | . 2 X O . .
$$ | . . X O . .
$$ | . a O . . .
$$ | . . . . . .
$$ +------------
Click Here To Show Diagram Code
[go]$$W $$ | . . . . . . $$ | . . 5 . . . $$ | . 3 X . . . $$ | . X O O . . $$ | 4 1 X O . . $$ | . 2 X O . . $$ | . . X O . . $$ | . a O . . . $$ | . . . . . . $$ +------------[/go]
I feel like whenever I see this sort of problem, the official solution (as determined by pros or their ghostwriters) is to cut inside and take the outside, rather than vice versa, but I'm not strong enough to be confident that it is really best. I am starting to develop an appreciation for this sort of ridiculous thickness, though. One extra thing it has going for it in this particular situation is that Black needs to play at a immediately just to live.

Anyway, all of this helps explain why in practice Black generally responds to the hane with a immediately.

I agree. This was probably the way to go in terms of joseki moves. I can't really articulate why, but for some reason, I can't help but feel that black is a step ahead of where she should be in this position from Bill's post:

Click Here To Show Diagram Code: [go]$$Wc Other $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . O . . . O X X . . . | $$ | . . . , . . . . . , . . . O O , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . 2 . . . . . . . . . . . . . . . . . | $$ | 4 1 X . . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | . 3 X O . . . . . . . . . . . . . . . | $$ | . . X O . . . . . , . . . X . O . . . | $$ | . 5 X O . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

That said, thank you all for the comments!

Posted: **Tue Sep 18, 2018 11:07 pm**

BlindGroup your comment about

is not correct, it is a good move. (The problem starts with

).

extending at S3 would be a loosing move after black ataris at Q5.

Posted: **Wed Sep 19, 2018 1:11 am**

Hi Gomoto,

... ... is a good move. The problem starts with

Thanks. Does the engine like just connect P4 for

?

Posted: **Wed Sep 19, 2018 7:45 am**

Thanks. Does the engine like just connect P4 for ?

It likes two times atari after crosscut

: bg.jpg (175.99 KiB) Viewed 14945 times

Click Here To Show Diagram Code: [go]$$B $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . O . . . O X X . . . | $$ | . . . , . . . . . , . . . O O , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . X O O . . . . . . . . . . . . . . . | $$ | . . X O . . . . . O . . . . . . O . . | $$ | . . X O . . . . . O X . . X O O X X . | $$ | . . X O . . . . . O X . . O O X O . . | $$ | . . O . . . . . O X . . . . X X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Posted: **Wed Sep 19, 2018 11:38 am**

Hi Gomoto,

It likes two times atari after crosscut

Thanks. Does the engine like this human sequence ?
( no whole board situation, sorry

)

Click Here To Show Diagram Code: [go]$$W $$ . . . . , . . . | $$ . . . . . . . . | $$ . . . . . O . . | $$ . . . . . . . . | $$ . . . . . X . . | $$ . . . . 3 5 . . | $$ . . . 4 X O . . | $$ . . . . O X 1 . | $$ . . . . . 2 . . | $$ . . . . . . . . | $$------------------[/go]

Posted: **Wed Sep 19, 2018 12:41 pm**

@EdLee: It does approve this variation.

Life In 19x19

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