spotting the atari and other issues (Mark's study journal)

Mark356 · Post by **Mark356** » Tue Jan 11, 2011 7:05 pm

I had a stupid moment the other day in an ASR League game against Edisson.

I was white in this game, and started as manego. The situation in the lower left corner started after I'd ignored an approach to play an approach of my own. I thought that move 1 here is a ladderbreaker:

Click Here To Show Diagram Code: [go]$$W Moves 18 to 18 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . O . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . 1 . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . a . . . . . . . . . . . . . . . . | $$ | . . X O . X . . . . . . . . . . . . . | $$ | . . . O X O . . . . . . . . . . . . . | $$ | . . . O X O X . . , . . . . . X . . . | $$ | . . . O X X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

His reply:

Click Here To Show Diagram Code: [go]$$B Moves 19 to 19 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . O . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . O 1 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X O . X . . . . . . . . . . . . . | $$ | . . . O X O . . . . . . . . . . . . . | $$ | . . . O X O X . . , . . . . . X . . . | $$ | . . . O X X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

After that, I confidently proceeded to play out the entire ladder, absolutely sure that my ladderbreaker was still working:

Click Here To Show Diagram Code: [go]$$W Moves 54 to 55 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . O . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . 2 . . . . | $$ | . . . . . . . . . . . . . X 1 O X . . | $$ | . . . . . . . . . . . . X O O X . . . | $$ | . . . . . . . . . . . X O O X . . . . | $$ | . . . . . . . . . . X O O X . . . . . | $$ | . . . , . . . . . X O O X . . , . . . | $$ | . . . . . . . . X O O X . . . . . . . | $$ | . . . . . . . X O O X . . . . . . . . | $$ | . . . . . . X O O X . . . . . . . . . | $$ | . . X O . X O O X . . . . . . . . . . | $$ | . . . O X O O X . . . . . . . . . . . | $$ | . . . O X O X . . , . . . . . X . . . | $$ | . . . O X X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

At which point I resigned.

Andrew, watching the game, pointed out a couple of things. First, I could easily have tenuki'd from the lower left corner a second time to attack the upper right. I'd already ignored one approach to it, so may as well get some advantage. Secondly, although there are some fighting joseki that work the hoshi with two approach stones, the situation in the lower left corner wasn't bad at all as I had it. If I'd simply played a hane instead of a ladderbreaker, "a" in the first diagram, the result would've been about equal. And finally, ladderbreaker or no, it's very silly to play out an entire ladder to save stones that aren't even cutting stones.

But if nothing else, I'll definitely remember that there's more than one way to break a ladder!

Mark356 · Post by **Mark356** » Sat Jan 15, 2011 12:31 am

I was playing through a Shuusaku game, the 1874 Oct. 21 game against Yasui Sanchi, and I came across this position:

Click Here To Show Diagram Code: [go]$$W Moves 22 to 23 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . O . 2 . . O . . . . | $$ | . . . , . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . Y . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X , . . . . . , . . . . . , O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . X , X . . . . , . . . O . O . . . | $$ | . . . . . . 1 . . . . . X X X X O O . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

I thought that move 23, move 2 in this diagram, was a peculiar tenuki. On the one hand, white has just created a weak invading group, and a play anywhere on the third line would threaten it: black could defend the corner, or else extend from the right, and either one would be sente.

More importantly, though, move 2 here seems to be in a very odd place to me. Yes, it's definitely sente, and it does have to be responded to. But it's deep enough into enemy territory that he has no chance at creating a base on the edge-- he's going to have to run. He's creating a weak running group. Furthermore, it's close enough to the triangled group that running and pushing could easily hurt it. In fact, when running he has to take a few moves to protect the triangled group rather than just run.

Looking at the way it played out to the end doesn't clarify things for me. The final board position (after which white resigned) is as follows:

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

I have triangled the move in question. It still doesn't look like a good move to me, because it neither contains much territory nor destroys much of white's. I can't see the purpose of the fight that that stone started at all.

Mark356 · Post by **Mark356** » Mon Jan 17, 2011 6:16 pm

I made a huge mistake in a game today.

I'd played a 3-4 point, my opponent had approached, and I'd tenuki'd to play another corner, so he pressed:

Click Here To Show Diagram Code: [go]$$W $$ -------------------- $$ . . . . . . . . . . | $$ . . . . . . . . . . | $$ . . . . . . Y . . . | $$ , . . . 1 . , . . . | $$ . . . . . . O . . . | $$ . . . . . . . . . . | $$ . . . . . . . . . . | $$ . . . . . . . . . . | $$ . . . . . . . . . . | $$ , . . . . . , . . . |[/go]

I jumped out and ran:

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

And I was sure that I could jump out rather than continue to push, since I'd read that several times before:

Click Here To Show Diagram Code: [go]$$B $$ -------------------- $$ . . . . . . . . . . | $$ . . . . . . . . . . | $$ . 1 . X X . X . . . | $$ , . O O O . , . . . | $$ . . . . . . O . . . | $$ . . . . . . . . . . | $$ . . . . . . . . . . | $$ . . . . . . . . . . | $$ . . . . . . . . . . | $$ , . . . . . , . . . |[/go]

After which point my opponent promptly cut off the two stones and got the corner with the following tesuji:

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

And now I've got neither corner territory nor outside influence. I resigned 92 moves later.

After the game, he pointed out several places where I could've played differently, even if I was going to tenuki before answering:

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

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

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

But I think my biggest mistake was this move here:

Click Here To Show Diagram Code: [go]$$B $$ -------------------- $$ . . . . . . . . . . | $$ . . . . . . . . . . | $$ . 1 . X X . X . . . | $$ , . O O O . , . . . | $$ . . . . . . O . . . | $$ . . . . . . . . . . | $$ . . . . . . . . . . | $$ . . . . . . . . . . | $$ . . . . . . . . . . | $$ , . . . . . , . . . |[/go]

When pushing from behind like this, this sort of jump does occur, but only after three stones. With two stones, they're vulnerable to the sort of cut that my opponent did, but three is OK. An example is in the joseki:

Click Here To Show Diagram Code: [go]$$B A basic joseki $$ ------------------ $$ | . . . . . . . . . $$ | . . 6 4 5 . . . . $$ | . . O 1 7 O . X . $$ | . . 2 X . . . . . $$ | . . . 3 . . . . . $$ | . . 8 . . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . .[/go]

There's also this joseki with the keima press:

Click Here To Show Diagram Code: [go]$$B Upper right $$ -------------------- $$ . . . . . . . . . . | $$ . . . . . . . . . . | $$ . 3 . . . 2 . . . . | $$ , . . . . . , 1 . . | $$ . . . . . . 4 5 . . | $$ . . . . . . 6 . . . | $$ . . . . . . . 7 . . | $$ . . . . . . . . . . | $$ . . . . . . . . . . | $$ , . . . . . , . . . |[/go]

Here, Black can jump after playing just two stones. But the two stones have enough liberties that this sort of cut isn't an issue yet, since they still have a liberty at the star point. This is very different from the situation I ran into.

I guess the moral of the story is to always read before you jump!

Mark356 · Post by **Mark356** » Mon Jan 17, 2011 9:37 pm

In this game, I was black. A 1k reviewing the game told me that the following move is overconcentrated:

Click Here To Show Diagram Code: [go]$$B Moves 53 to 53 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . X . . . . | $$ | . . . . . . . . . . . . . X . X O . . | $$ | . . . X . . . . . X . . O . X O O . . | $$ | . . . , . . . . . , . . . . X O . O . | $$ | . . . 1 . . . . . . X . . . . X O O . | $$ | . . . . . . . . . . . . . . X . X X . | $$ | . . . . . . . . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . . O O . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . O . | $$ | . . . . . . . . . . . . . O . O O X . | $$ | . . . . . . . . . . . . . . X O X . X | $$ | . . . . . . . . . . . . . O O X X X . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . , . . . . . O . . . . . O X X . | $$ | . . O . . . . . . . . . . . . O O X . | $$ | . . . . . . . . . . . . . . . . . O . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

I thought that it was a beautiful move: it protects about 40 points of territory along the top and threatens to take far more.

The reviewer had a different perspective. He thought that my position on top was already quite stable, and if white tries to invade he'll just end up solidifying territory for me:

Click Here To Show Diagram Code: [go]$$W Moves 53 to 53 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . X . . . . | $$ | . . . . . . . . . . . . . X . X O . . | $$ | . . . X . . . . . X . . O . X O O . . | $$ | . . . , . 2 . . . , . . . . X O . O . | $$ | . . . 1 . . . . . . X . . . . X O O . | $$ | . . . . . . . . . . . . . . X . X X . | $$ | . . . . . . . . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . . O O . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . O . | $$ | . . . . . . . . . . . . . O . O O X . | $$ | . . . . . . . . . . . . . . X O X . X | $$ | . . . . . . . . . . . . . O O X X X . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . , . . . . . O . . . . . O X X . | $$ | . . O . . . . . . . . . . . . O O X . | $$ | . . . . . . . . . . . . . . . . . O . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

I forget the rest of the line of play that he suggested. But rather than protecting what's already mine, he said that it's time for a 4-4 attack, or at least something like a 5-4, on that lone 3-3.

Another reviewer, of about the same rank, had a slightly different opinion. He said that because c3 is a 3-3 rather than hoshi, I can approach it at any time with 4-4 and live within the white moyo. In fact, both reviewers said that white's choice of 3-3 seems slightly inconsistent with his moyo on the bottom. A 3-3 attack on a hoshi only solidifies the moyo; a 4-4 attack on a 3-3 lives within the moyo. But because of that, this move might be slow, but it's not overconcentrated. However, if the 3-3 were a hoshi, then it would definitely be time to approach.

But neither reviewer answered the bigger question: how can I tell if a move is going to make my position overconcentrated? What's the difference between honte, slow, and overconcentrated?

Redundant · Post by **Redundant** » Mon Jan 17, 2011 10:02 pm

Click Here To Show Diagram Code: [go]$$B Moves 53 to 53 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . X . . . . | $$ | . . . . . . . . . . . . . X . X O . . | $$ | . . . X . . . . . X . . O . X O O . . | $$ | . . . , . . . . . , . . . . X O . O . | $$ | . . . 1 . . . . . . X . . . . X O O . | $$ | . . . . . . . . . . . . . . X . X X . | $$ | . . . . . . . . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . . O O . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . O . | $$ | . . . . . . . . . . . . . O . O O X . | $$ | . . . . . . . . . . . . . . X O X . X | $$ | . . . . . . . . . . . . . O O X X X . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . b . . . . . O . . . . . O X X . | $$ | . . O . . . . . . . . . . . . O O X . | $$ | . . . . . . . . . . . . . . . . . O . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

I think that this makes beautiful shape on the top. Globally, I think that b might be better. However, I definitely don't think that the enclosure here is overconcentrated.

Mark356 · Post by **Mark356** » Wed Feb 09, 2011 8:10 am

Thanks, it's good to get another opinion on it.

Mark356 · Post by **Mark356** » Wed Feb 09, 2011 8:37 am

I saw an interesting move in a game that Aguilar played the other day.

The board looks like this. Black had just played the upper-left shimari:

Click Here To Show Diagram Code: [go]$$ Position at move 37 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . X . . . . . | $$ | . . . X . . . . . , . . . . . X . X . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . O , O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . O . . . . . | $$ | . . . . . . . . . . X . . . O . . . . | $$ | . . O , X . X . . , . . O O X O O O . | $$ | . . . O O X . . . . X . O X X X X O . | $$ | . . . . . . . . . . . . O O X . . X X | $$ | . . . . . . . . . . . . . . . . X . . | $$ ---------------------------------------[/go]

Where to play next? The left is all low, and both black and white have a toehold, so although there's going to be fighting there, it's not time yet. But on the top, Black has a 9-space gap, and one of the stones is high. So White should be able to either approach the hoshi, or just wedge in there. If White wedges, Black can't prevent White from getting a 2-space extension. So far so good.

However, a 2-space extension really doesn't look all that good for White:

Click Here To Show Diagram Code: [go]$$W Moves 38 to 40 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 4 . . . . . . . . . . . . . . . | $$ | . . . . . 3 . . 1 . 2 . . X . . . . . | $$ | . . . X . . . . . , . . . . . X . X . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . O , O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . O . . . . . | $$ | . . . . . . . . . . X . . . O . . . . | $$ | . . O , X . X . . , . . O O X O O O . | $$ | . . . O O X . . . . X . O X X X X O . | $$ | . . . . . . . . . . . . O O X . . X X | $$ | . . . . . . . . . . . . . . . . X . . | $$ ---------------------------------------[/go]

If White played like this, his 2-point jump would be undercut immediately. Black has stones he can run to on either side, so White can't prevent Black from jumping in. White has a presence, yes, but no eyespace.

But that's not what White does. He plays like this:

Click Here To Show Diagram Code: [go]$$W Moves 38 to 40 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . 3 . . . . . . . . . . . . . . | $$ | . . . . . . . . 1 . 2 . . X . . . . . | $$ | . . . X . . . . . , . . . . . X . X . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . O , O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . O . . . . . | $$ | . . . . . . . . . . X . . . O . . . . | $$ | . . O , X . X . . , . . O O X O O O . | $$ | . . . O O X . . . . X . O X X X X O . | $$ | . . . . . . . . . . . . O O X . . X X | $$ | . . . . . . . . . . . . . . . . X . . | $$ ---------------------------------------[/go]

He makes a 3-point extension onto the second line! I've seen this 3-point extension before, with the order reversed: the second-line play serving as an approach, and when the opponent defends, to play the 3-point jump. (I may have even seen a 4-point jump from the approach, treating the approach stone lightly. Of course, with the order reversed, you give the opponent the option to hem you in and let you live small in the corner instead.)

This stone looked a bit floppy to me at first: normally you can either split the very large knight's move, or you can live under it. However, the normal sequence doesn't work here, because it's the second line:

Click Here To Show Diagram Code: [go]$$B Moves 38 to 40 $$ --------------------------------------- $$ | . . . . . . 7 . . . . . . . . . . . . | $$ | . . . . O 5 2 3 . . . . . . . . . . . | $$ | . . . . . 6 1 4 O . X . . X . . . . . | $$ | . . . X . . 8 . . , . . . . . X . X . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . O , O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . O . . . . . | $$ | . . . . . . . . . . X . . . O . . . . | $$ | . . O , X . X . . , . . O O X O O O . | $$ | . . . O O X . . . . X . O X X X X O . | $$ | . . . . . . . . . . . . O O X . . X X | $$ | . . . . . . . . . . . . . . . . X . . | $$ ---------------------------------------[/go]

And Black would be trapped. So this 3-point jump is not alive yet, but it's at least safe from that.

Of course, this 3-point jump isn't free. Black got 2 types of compensation.

First, the white stones are so low that Black was able to get a lot of thickness above:

Click Here To Show Diagram Code: [go]$$W Moves 40 to 45 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 2 1 5 . . . . . . . . . . . . . | $$ | . . . . 4 3 . . O . X . . X . . . . . | $$ | . . . X . 6 . . . , . . . . . X . X . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . O , O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . O . . . . . | $$ | . . . . . . . . . . X . . . O . . . . | $$ | . . O , X . X . . , . . O O X O O O . | $$ | . . . O O X . . . . X . O X X X X O . | $$ | . . . . . . . . . . . . O O X . . X X | $$ | . . . . . . . . . . . . . . . . X . . | $$ ---------------------------------------[/go]

The other compensation that Black got was that although there's definitely space for one eye under there, there's not really room for two. White had to run for life, and eventually connected out to the stones on the right side. If White didn't have stones on the right, perhaps he shouldn't have played this way at all. But there's a big difference between running with no eyes and running with one eye. I'll definitely want to remember this move.

Mark356 · Post by **Mark356** » Fri Mar 18, 2011 5:27 am

I was reading Lessons in the Fundamentals of Go and one thing caught my attention. It's from chapter 5, on spheres of influence, and how territory you have some claim over isn't really yours yet, nor should it always be defended. On page 103:

Click Here To Show Diagram Code: [go]$$c This is a label for the diagram. $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . a Q O . . . . . . . . . | $$ | . . . . . . b . X O . . . O O X . . . | $$ | . . . X . X . . X X O O O X . X . . . | $$ | . . . . . . . . . . X X X X . . . . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]

This is part of a whole-board exercise: White has just played the marked stone. But the point that got my attention was the sentence: "The most natural thing in the world is for Black to answer at A or B, but if he does not rid himself of this habit of answering, he cannot hope to make progress." He goes on to say that Black should use this point as an opportunity to take control of the game and play somewhere else important, and he'll come out ahead even if he does lose the upper left corner. The right answer in the exercise is where and how Black should invade to make the most of his thickness.

Situations like this come up all the time in my games. My opponent will play a move similar to the marked one, often fairly early, and I'll keep on blocking all the way even though I know it's not time for yose yet. It always pains me to do so, but I always think about the damage my opponent could inflict if I don't answer.

Anyway, I tried ignoring a threat to crawl under in favor of taking an important point elsewhere:

Click Here To Show Diagram Code: [go]$$B Moves 18 to 19 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . X X O . . . . 2 . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . O O 1 . | $$ | . . X . . . . . . . . . . . . . X . . | $$ | . . . X . . . . . , . . . . . X . . . | $$ | . . . . . . X . . . . . X . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

(From Zombieboy vs. Shinanami, 3 stones, 3/18.)

I ignored her follow-up as well:

Click Here To Show Diagram Code: [go]$$B Moves 20 to 21 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . X X O . . . . O . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . . . . . . . . 2 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . 1 a . | $$ | . . O O . . . . . . . . . . . O O X . | $$ | . . X . . . . . . . . . . . . . X . . | $$ | . . . X . . . . . , . . . . . X . . . | $$ | . . . . . . X . . . . . X . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

I think her follow-up was a mistake-- if she wanted to follow up, she shouldn't have left the cutting point at "a". Anyway, I'd already expressed my willingness to give up that part of the board in exchange for benefits elsewhere, so I was even happier that I had a chance to cut:

Click Here To Show Diagram Code: [go]$$W Moves 25 to 31 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . X X O . . . . O . . . 2 . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . X . . . . . . . . . . . . . X . . | $$ | . . . X . . . . . . . . . . . O O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . 7 . | $$ | . . . . . . . . . . . . . . . X X 5 . | $$ | . . O O . . . . . . . . . . 1 O O X . | $$ | . . X . . . . . . . . . . . . . X 3 6 | $$ | . . . X . . . . . , . . . . . X . 4 . | $$ | . . . . . . X . . . . . X . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

After this I had only one weak group, my other local stones were connected, and I'd cut off black's stones and was able to get a lot of influence from attacking them later. I did go on to win the game, but I think she could've answered better as well. Maybe just connecting at A as soon as I made the first cut, for instance. I wonder if I'd won the game anyway if Black had successfully undermined my sphere of influence.

Shaddy · Post by **Shaddy** » Fri Mar 18, 2011 2:09 pm

A small but important detail: in Lessons, black's group is absolutely alive. The only thing white could destroy by the second-line move is territory. In your game, black's move threatens to take your base, and it is quite important to answer.

Mark356 · Post by **Mark356** » Sun May 08, 2011 5:54 pm

Oh, right! I knew that that hane made me uncomfortable. Quite a big difference, now that you mention it.

Mark356 · Post by **Mark356** » Sun May 08, 2011 6:08 pm

I was white in this game. Black kicked all my approaches, so I thought this opening went a bit oddly. Anyway, white to play:

Click Here To Show Diagram Code: [go]$$ Position at move 19 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . X . X . . . | $$ | . . X , . . . X . , . . . . . , X . . | $$ | . . . . X . . . . . . . . . . O O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X , . . . . . X . . . . . , O . . | $$ | . . . X . X . . . . . . . . O . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

I figured that the middlegame should start now, that everything that could expand without conflict had already expanded, and so it was time to invade. I decided to invade the top, because that way, if I got a strong group, I could get a good attack on at least one of Black's top right and top left. So I played right in the middle, like so:

Click Here To Show Diagram Code: [go]$$W Moves 20 to 20 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . X . X . . . | $$ | . . X , . . . X . , 1 . . . . , X . . | $$ | . . . . X . . . . . . . . . . O O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X , . . . . . X . . . . . , O . . | $$ | . . . X . X . . . . . . . . O . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Of course, Black easily proved that this was a very bad move:

Click Here To Show Diagram Code: [go]$$W Moves 20 to 25 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . X . X . . . | $$ | . . X , . . . X . , 1 . 2 . . , X . . | $$ | . . . . X . . . . 4 5 . . . . O O . . | $$ | . . . . . . . . . . 3 . 6 . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X , . . . . . X . . . . . , O . . | $$ | . . . X . X . . . . . . . . O . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Now White has a weak floating group in the middle of the board, Black is reasonably strong on both sides, and White cannot easily both make good on the early claim to the top right side and make the weak group strong. Taking care of this group was a big issue for me, and I only made it live and got it out when Black slackened the attack on it later. So invading here was a very bad idea from the start.

I asked Rosi, a 1k who used to be in my ASR class, where White should move instead of invading. Clearly, invading like that is too good for Black. Here is her reply:

Click Here To Show Diagram Code: [go]$$W Position at move 19 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . X . X . . . | $$ | . . X , . . . X . , 2 . . . . , X . . | $$ | . . . . X . . . . . . . 1 . . O O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X , . . . . . X . . . . . , O . . | $$ | . . . X . X . . . . . 3 . . O . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Her answer is that it's not time to invade yet in this game, that White still has a lot of very easy ways to expand its moyo yet. I hadn't even thought of this White 1!

SoDesuNe · Post by **SoDesuNe** » Mon May 09, 2011 6:42 am

I really don't like :w1:

and

. White has two overextended shapes (top left and bottom right), where Black can easily invade or just reduce.
:w1:

just solidies Black it does not even reduce effectivly.
:w3:

takes maybe a bit of territory and might aim at pincering the Black stone. But it's on the fourth line, so a pincer is not even severe. My question is: What does White gain with these moves?

I, too, would have invaded the top side. Maybe at the Hoshi. Black is very loose on the top left side and they surely is a lot of Aji to exploit for White. Though I think White will get trouble with its overextended shape in the top left.

Life In 19x19

spotting the atari and other issues (Mark's study journal)

facepalm moment

Shuusaku oddity

Re: spotting the atari and other issues (Mark's study journa

overconcentrated

Re: spotting the atari and other issues (Mark's study journa

Re: spotting the atari and other issues (Mark's study journa

second-line extension

Re: spotting the atari and other issues (Mark's study journa

Re: spotting the atari and other issues (Mark's study journa

Re: spotting the atari and other issues (Mark's study journa

late opening issue

Re: spotting the atari and other issues (Mark's study journa