Life In 19x19

I have very little experience with this variation, so I'd like to learn more about it.

The Intrepid wrote:Now the question is whether White will choose the usual--gote--variation or if he'll sacrifice points for sente.

Click Here To Show Diagram Code

[go]$$Wcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 9 7 8 . . . . . . . . . . . . . . |
$$ | . . O X . 0 . . . . . . . . . . . . . |
$$ | . . 1 X . . . . . , . . . . . , . . . |
$$ | . 3 2 . . . . . . . . . . . . . . . . |
$$ | . 5 4 . . . . . . . . . . . . . . . . |
$$ | . . 6 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

This one is no more joseki, not "the usual--gote--variation". It is considered not enough for black.

[edit] viewtopic.php?p=125363#p125363 [/edit]

I disagree that that sequence is no longer joseki. It is a highly situation dependent result. In the diagram you posted, namely an empty board apart from the 4-4 invaded underneath, that result is good for black. The 3-3 invasion is more usually played when black has made a double wing formation from his 4-4 and in that case following that standard sequence can result in one or both of the wing stones becoming inefficient and this transforms the result towards even and then good for white depending on how inefficient black's existing stones become. The example you posted in your lecture series has these wing stones.

I heard this several times from BadukTV. With the night's move instead of hane, black (with 4-4)

1. has better endgame moves later
2. is little bit thicker then the hane variation
3. can consider tenuki

Therefore, the hane variation is no longer called as joseki, or played.

Do you mean the following diagram is not jeseki in general or that it is not joseki only when Black has a double-wing formation?

Click Here To Show Diagram Code

[go]$$Wcm1
$$ ----------------
$$ | . . . . . . .
$$ | . . 9 7 8 . .
$$ | . . O X . 0 .
$$ | . . 1 X . . .
$$ | . 3 2 . . . .
$$ | . 5 4 . . . .
$$ | . . 6 . . . .
$$ | . . . . . . .[/go]

I expect the following. Then, if this happens, I get sente, which I'd be very happy with.

Click Here To Show Diagram Code

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

However, let's go back and take a look at some of the other good choices EdLee had for his previous move. First, the sente variation:

Click Here To Show Diagram Code

[go]$$Wc
$$ ------------------
$$ | . . . . . . . .
$$ | . . . . . . . .
$$ | . . X O . . . .
$$ | . . X O . . . .
$$ | . . . . . . . .
$$ | . 2 1 . . . . .
$$ | . . . . . . . .
$$ | . . . . . . . .
$$ | . . . . . . . .
$$ | . . O , . . . .
$$ | . . . . . . . .[/go]

White can tenuki with but has to content himself with the possibility of Black playing this follow-up:

Click Here To Show Diagram Code

[go]$$Bcm4
$$ ------------------
$$ | . . . . . . . .
$$ | . . . . . . . .
$$ | . . X O . . . .
$$ | . . X O . . . .
$$ | . . . . . . . .
$$ | . X O 2 . . . .
$$ | . . 1 . . . . .
$$ | . 3 . . . . . .
$$ | . . . . . . . .
$$ | . . O , . . . .
$$ | . . . . . . . .[/go]

White takes sente again, but the lone White stone on the left gets isolated, Black takes a fair bit of territory, and Black threatens to invade the center (unless White blocks, but then Black takes sente).

Second, since White has a stone at J7--which functions as a ladder breaker--White can consider this variation:

Click Here To Show Diagram Code

[go]$$Wc
$$ --------------------
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . X O . . . . .
$$ | . 3 X O . . . . .
$$ | . 2 1 . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . O , . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . W[/go]

Because of the ladder-breaker, Black cannot go for the following variation:

Click Here To Show Diagram Code

[go]$$Bcm4
$$ --------------------
$$ | . . . . . . . . .
$$ | . 4 3 5 6 . . . .
$$ | . 2 X O . . . . .
$$ | . O X O . . . . .
$$ | . X O . . . . . .
$$ | . 1 . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . O , . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . W[/go]

Click Here To Show Diagram Code

[go]$$Bcm10
$$ --------------------
$$ | . . . . . . . . .
$$ | . O X X O . . . .
$$ | . O X O 3 . . . .
$$ | . O X O 4 8 . . .
$$ | . X O 1 7 . . . .
$$ | . X 2 6 9 . . . .
$$ | . . 5 0 . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . O , . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . W[/go]

This ladder does not work for Black, so his position collapses.

Therefore, Black would have to choose between the following two options. First, he could live small but get sente:

Click Here To Show Diagram Code

[go]$$Bcm4
$$ --------------------
$$ | . . . . . . . . .
$$ | . . . a . . . . .
$$ | . 1 X O . . . . .
$$ | 3 O X O . . . . .
$$ | . X O . . . . . .
$$ | . 2 4 . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . O , . . . . .
$$ | . . . . . . . . .[/go]

Later, White has a big endgame move at "a" which threatens a big ko in the corner.

Second, Black could choose to get more territory but at the cost of taking gote (although here, too, Black would be threatening to invade the center):

Click Here To Show Diagram Code

[go]$$Bcm4
$$ --------------------
$$ | . . . . . . . . .
$$ | . . 2 1 4 . . . .
$$ | . 3 X O . . . . .
$$ | . O X O . . . . .
$$ | . X O 6 . . . . .
$$ | . . 5 . . . . . .
$$ | . 7 . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . O , . . . . .
$$ | . . . . . . . . .[/go]

Another possibility which White could have considered is hane from the other side:

Click Here To Show Diagram Code

[go]$$Wc
$$ ------------------
$$ | . . . . . . . .
$$ | . 2 1 3 . . . .
$$ | . . X O . . . .
$$ | . . X O . . . .
$$ | . . . 5 . . . .
$$ | . . 4 b . . . .
$$ | . a . . . . . .
$$ | . . . . . . . .
$$ | . . . . . . . .
$$ | . . O , . . . .
$$ | . . . . . . . .[/go]

Black can next choose between "a" and "b." Also, White might tenuki instead of playing .

Overall, it seems to me that all of these choices are okay for Black. Let's see how the game proceeds, and then we'll be able to decide if any of the above variations would have been better or worse than the game.

In preparation I was thinking of the hane :

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[go]$$W
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . . . . . . . O O . . |
$$ | . . X O . . . . . , . O . O . O X . . |
$$ | . . X O . . . . . . . . . . . X . . . |
$$ | . . 1 . . . . . . . . . X . . . X . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . X . . . X O . . |
$$ | . . O , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . O . . . . . . . . |
$$ | . . . . . . . . O . X O O O . O . . . |
$$ | . . . . . . . . . . O X X X O . . . . |
$$ | . . . . . . . . . X X . . . X O . . . |
$$ | . . . , . . . . . , . . . . X , . . . |
$$ | . . X . . . . . X . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]

I believe White should next protect one of the cutting points in the top-left corner. After this, I'll carefully review the situation on the board to verify that I am actually ahead, like I think I am. If my current evaluation of the position holds, I intend to play this:

Click Here To Show Diagram Code

[go]$$Bc
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X X O . . . . . . . . . . . . . . |
$$ | . . X O . . . . . . . . . . . O O . . |
$$ | . . X O . . . . . 2 . O . O . O X . . |
$$ | . . X O . . . . . . . . . . . X . . . |
$$ | . . O O . . . . . . 1 . X . . . X . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . X . . . X O . . |
$$ | . . O , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . O . . . . . . . . |
$$ | . . . . . . . . O . X O O O . O . . . |
$$ | . . 3 . . . . . . . O X X X O . . . . |
$$ | . . . . . . . . . X X . . . X O . . . |
$$ | . . . , . . . . . , . . . . X , . . . |
$$ | . . X . . . . . X . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]

However, if it turns out my earlier assessment of the position was wrong, I will invade:

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[go]$$Bc
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X X O . . . . . . . . . . . . . . |
$$ | . . X O . . . . . 1 . . . . . O O . . |
$$ | . . X O . . . . . , . O . O . O X . . |
$$ | . . X O . . . . . . . . . . . X . . . |
$$ | . . O O . . . . . . . . X . . . X . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . X . . . X O . . |
$$ | . . O , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . O . . . . . . . . |
$$ | . . . . . . . . O . X O O O . O . . . |
$$ | . . . . . . . . . . O X X X O . . . . |
$$ | . . . . . . . . . X X . . . X O . . . |
$$ | . . . , . . . . . , . . . . X , . . . |
$$ | . . X . . . . . X . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]

I think about just connecting at :

Click Here To Show Diagram Code

[go]$$W
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X X O . . . . . . . . . . . . . . |
$$ | . . X O . . . . . . . . . . . O O . . |
$$ | . . X O . . . . . , . O . O . O X . . |
$$ | . . X O . . . . . . . . . . . X . . . |
$$ | . . O 1 . . . . . . . . X . . . X . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . X . . . X O . . |
$$ | . . O , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . O . . . . . . . . |
$$ | . . . . . . . . O . X O O O . O . . . |
$$ | . . . . . . . . . . O X X X O . . . . |
$$ | . . . . . . . . . X X . . . X O . . . |
$$ | . . . , . . . . . , . . . . X , . . . |
$$ | . . X . . . . . X . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]

This local shape is apparently quite rare in pro games -- only 2 out of a search of 50,744 games,
and in both cases, the pro move was connect at , not the tiger's mouth in the game.

Click Here To Show Diagram Code

[go]$$W
$$ -------------------
$$ | . . . . . . . . .
$$ | . . X X O a . . .
$$ | . . X O . b . . .
$$ | . . X O . . . . .
$$ | . c X O . . . . .
$$ | . . O 1 . . . . .
$$ | . . . . . . . . .[/go]

However, I don't understand . Therefore, .

A few things obvious about the solid connect:
- can clamp (a);
- can peep (b);
- hane (c) + connect is sente.

EdLee wrote:However, I don't understand . Therefore, .

allows you to safely block at which is a huge difference (about 10 points), basics Your move is a bit stronger on the top side, but the left side loss is much bigger and a big failure to punish black's order mistake.

Click Here To Show Diagram Code

[go]$$W
$$ -------------------
$$ | . . . . . . . . .
$$ | . . X X O . . . .
$$ | . . X O . . . . .
$$ | . . X O . . . . .
$$ | . . X O . . . . .
$$ | . 2 O 1 . . . . .
$$ | . 3 . . . . . . .
$$ | . . . . . . . . .[/go]

Black should have hane'd on the left before on top, in which case the below probably happens. It might revert to this end result, but white lost a chance to improve on it.

Click Here To Show Diagram Code

[go]$$Bm47
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 7 5 6 . . . . . . . . . . . . . . |
$$ | . . X O . 8 . . . . . . . . . O O . . |
$$ | . . X O . . . . . , . O . O . O X . . |
$$ | . . X O . . . . . . . . . . . X . . . |
$$ | . 1 O . . . . . . . . . X . . . X . . |
$$ | . 3 2 . . . . . . . . . . . X . . . . |
$$ | . . 4 . . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . X . . . X O . . |
$$ | . . O , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . O . . . . . . . . |
$$ | . . . . . . . . O . X O O O . O . . . |
$$ | . . . . . . . . . . O X X X O . . . . |
$$ | . . . . . . . . . X X . . . X O . . . |
$$ | . . . , . . . . . , . . . . X , . . . |
$$ | . . X . . . . . X . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]

Uberdude, thanks.