Life In 19x19

Joaz Banbeck wrote:This is three moves in a row in which I am totally befuddled by my opponent's moves.

For the third Joaz-befuddling move, I'm guessing Magicwand played it to give the corner slightly better eyeshape. Let's ignore the cutting potential at E15, giving black an extra stone there.

If white plays the usual connection then black's block is sente:

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[go]$$Wcm1 Sente
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 1 O . O 2 . . . . . . . . . X . . . |
$$ | . O X O . X . . . . O . . O . . . . . |
$$ | . X X , . X O . . X . . . . . X . . . |
$$ | . . . X . B . O X O O O X . O O X . . |
$$ | . . . . . . . . O X O X O . . X . . .[/go]

Because if white ignores, he dies:

Click Here To Show Diagram Code

[go]$$Bcm1 Dead
$$ ---------------------------------------
$$ | . 3 . . . 4 . . . . . . . . . . . . . |
$$ | 2 O O . O X 5 . . . . . . . . X . . . |
$$ | 1 O X O . X . . . . O . . O . . . . . |
$$ | . X X , . X O . . X . . . . . X . . . |
$$ | . . . X . X . O X O O O X . O O X . . |
$$ | . . . . . . . . O X O X O . . X . . .[/go]

Whereas if white plays as in the game, he can ignore B2 and still have the corner survive.

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[go]$$Wcm1 Not sente
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . O 2 . . . . . . . . . X . . . |
$$ | 1 O X O . X . . . . O . . O . . . . . |
$$ | . X X , . X O . . X . . . . . X . . . |
$$ | . . . X . X . O X O O O X . O O X . . |
$$ | . . . . . . . . O X O X O . . X . . .[/go]

Because black has to stop W4 from escaping, so white can make enough eyeshape to live:

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[go]$$Bcm1 Black can't kill
$$ ---------------------------------------
$$ | 3 1 . . . 4 . . . . . . . . . . . . . |
$$ | . 2 O . O X 5 . . . . . . . . X . . . |
$$ | O O X O 6 X . . . . O . . O . . . . . |
$$ | . X X , . X O . . X . . . . . X . . . |
$$ | . . . X . X . O X O O O X . O O X . . |
$$ | . . . . . . . . O X O X O . . X . . .[/go]

If black instead preempts W4, white lives with a standard 1-1 throw-in and squeeze.

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[go]$$Bcm1 Black can't kill
$$ ---------------------------------------
$$ | 4 1 . . 3 . . . . . . . . . . . . . . |
$$ | . 2 O . O X . . . . . . . . . X . . . |
$$ | O O X O . X . . . . O . . O . . . . . |
$$ | . X X , . X O . . X . . . . . X . . . |
$$ | . . . X . X . O X O O O X . O O X . . |
$$ | . . . . . . . . O X O X O . . X . . .[/go]

Note that although white can live, doing so crucially depends on the ability to connect out to his other stones. If black insists, he can keep white to 1 eye locally, so white must survive by connecting out:

Click Here To Show Diagram Code

[go]$$Bcm1 White lives by escaping
$$ ---------------------------------------
$$ | 3 1 . . 6 4 5 . . . . . . . . . . . . |
$$ | . 2 O . O X 8 0 . . . . . . . X . . . |
$$ | O O X O 7 X 9 . . . O . . O . . . . . |
$$ | . X X , . X O . . X . . . . . X . . . |
$$ | . . . X . X . O X O O O X . O O X . . |
$$ | . . . . . . . . O X O X O . . X . . .[/go]

This last point means that if white ignores black's block at F18, any subsequent move by black in the top area is sente against the corner, because it would prevent the above connection sequence. So black's block might still be pretty strong because of the bad aji left for white, and I'm a bit unsure how to value it against the loss of two points endgame on the left from descending at A17 instead of connecting. But overall, white's move seems plausible to me.

something like below is probably correct move for white... but i still need to play catch up and below is not good enough...

Click Here To Show Diagram Code

[go]$$Bcm1 Prisoners: none
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . O . . . . . . . . . . X . . . |
$$ | O O X O . X . . . . O . . O . . . . . |
$$ | . X X , . X O . . X . . . . . X . . . |
$$ | . . . X . . . O X O O O X . O O X . . |
$$ | . . . . . X . . O X O X O . . X . . . |
$$ | . . . . . . . . . . X . . . . . X . . |
$$ | . . . . . . . . . X O O O O . O . . . |
$$ | . . X . . . . . . X X X X . . . . . . |
$$ | . . . W . . . . . , . . . X . , X . . |
$$ | . . . . . . . . . . . . O O X X . . . |
$$ | . . . . . . . . . . . . O X O . . . . |
$$ | . . . . . . . . . . . . O X O X . . . |
$$ | . . . . . . . . . . . . O . O O O . . |
$$ | . . . . . . . . . . . . X . . . . . . |
$$ | . . . X . . . . . , . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Must keep my head out.
BTW, that is now 4 moves in a row that I don't understand. At first glance it looks like a broken shape.

If i can get sente here then i will be ok. That will be big IF.

Yeah that broken shape looks bad for W. He aims at p3, but with o5 as black's sente even that is not so easy.

some comment on opponent's move
His move leaves bad aji.
if i was Joaz i would have connected solid as below.

Click Here To Show Diagram Code

[go]$$Bcm1 Prisoners: none
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . O . . . . . . . . . . X . . . |
$$ | O O X O . X . . . . O . . O . . . . . |
$$ | . X X , . X O . . X . . . . . X . . . |
$$ | . . . X B . . O X O O O X . O O X . . |
$$ | . . . . . C . . O X O X O . . X . . . |
$$ | . . . . . . . . . . X . . . . . X . . |
$$ | . . . . . . . . . X O O O O . O . . . |
$$ | . . X . . . . . . X X X X . . . . . . |
$$ | . . . , . . . . . , . . . X . , X . . |
$$ | . . . . . . . . . . . . O O X X . . . |
$$ | . . . . . . . . . . . . O X O . . . . |
$$ | . . . . . . . . . . . . O X O X . . . |
$$ | . . . . . . . . . . . . O . O O O . . |
$$ | . . . . . . . . . . . . X . . . . . . |
$$ | . . . X . . . . . , . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I've got to give MW credit where credit is due: he is very good at maintaining sente.

If this were a casual game, I'd slam a stone down at H4 without looking twice, and let the devil take the hindmost. But Ishida said that D6 is the play 90+% of the time.

I must take some time to look at this. We are currently on vacation in BC, Canada, so it may be a few days.

Let me know if you come near Vernon. I have the bare-bones start of a Go club at the library on Sundays and would love a lesson.

It looks like I'm not going to be able to upload video anytime soon. So I'm going to catch up on comments the old fashioned way. Let's go back a few moves, where it was white to play in this position:

Click Here To Show Diagram Code

[go]$$Wcm1 Prisoners: none
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . O . . . . . . . . . . X . . . |
$$ | . . X O . X . . . . O . . O . . . . . |
$$ | . . X , . X O . . X . . . . . X . . . |
$$ | . . . X . . . O X O O O X . O O X . . |
$$ | . . . . . . . . O X O X O . . X . . . |
$$ | . . . . . . . . . . X . . . . . X . . |
$$ | . . . . . . . . . X O O O O . O . . . |
$$ | . . X . . . . . . X X X X . . . . . . |
$$ | . . . , . . . . . , . . . X . , X . . |
$$ | . . . . . . . . . . . . O O X X . . . |
$$ | . . . . . . . . . . . . O X O . . . . |
$$ | . . . . . . . . . . . . O X O X . . . |
$$ | . . . . . . . . . . . . O . O O O . . |
$$ | . . . . . . . . . . . . X . . . . . . |
$$ | . . . X . . . . . , . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

At this point, I think that white made a mistake by playing at 'a'. There are two reasons for that opinion.
1) The important part of the board is around the shaded area, and it is soon going to switch to the lower part of the board. Playing in the corner is worth a few points, but it is out in the boondocks right now.

Click Here To Show Diagram Code

[go]$$Bcm1 Prisoners: none
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . O ? ? ? . . . . . . . X . . . |
$$ | . a X O . X ? ? . . O . . O . . . . . |
$$ | . . X , . X O ? . X . . . . . X . . . |
$$ | . . . X ? ? ? O X O O O X . O O X . . |
$$ | . . . . ? ? ? ? O X O X O . . X . . . |
$$ | . . . . . ? ? ? ? . X . . . . . X . . |
$$ | . . . . . ? ? ? ? X O O O O . O . . . |
$$ | . . X . . . . . . X X X X . . . . . . |
$$ | . . . , . . . . . , . . . X . , X . . |
$$ | . . . . . . . . . . . . O O X X . . . |
$$ | . . . . . . . . . . . . O X O . . . . |
$$ | . . . . . . . . . . . . O X O X . . . |
$$ | . . . . . . . . . . . . O . O O O . . |
$$ | . . . . . . . . . . . . X . . . . . . |
$$ | . . . X . . . . . , . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

2) White has two problems: his upper territory is about to be invaded, and his upper left corner is in danger. By playing in the corner, he only solves one of those problems.
But this would solve both:

Click Here To Show Diagram Code

[go]$$Wcm1 Prisoners: none
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . O . 1 . . . . . . . . X . . . |
$$ | . . X O . X . . . . O . . O . . . . . |
$$ | . . X , . X O . . X . . . . . X . . . |
$$ | . . . X . . . O X O O O X . O O X . . |
$$ | . . . . . . . . O X O X O . . X . . . |
$$ | . . . . . . . . . . X . . . . . X . . |
$$ | . . . . . . . . . X O O O O . O . . . |
$$ | . . X . . . . . . X X X X . . . . . . |
$$ | . . . , . . . . . , . . . X . , X . . |
$$ | . . . . . . . . . . . . O O X X . . . |
$$ | . . . . . . . . . . . . O X O . . . . |
$$ | . . . . . . . . . . . . O X O X . . . |
$$ | . . . . . . . . . . . . O . O O O . . |
$$ | . . . . . . . . . . . . X . . . . . . |
$$ | . . . X . . . . . , . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

It looks thin, but to the best of my calculations, it holds:

Click Here To Show Diagram Code

[go]$$Wcm1 Prisoners: none
$$ ---------------------------------------
$$ | . . . . . 5 7 . . . . . . . . . . . . |
$$ | . . O . O 4 1 6 . . . . . . . X . . . |
$$ | . . X O . X 2 3 . . O . . O . . . . . |
$$ | . . X , . X O 9 . X . . . . . X . . . |
$$ | . . . X . . 8 O X O O O X . O O X . . |
$$ | . . . . . . . . O X O X O . . X . . . |
$$ | . . . . . . . . . . X . . . . . X . . |
$$ | . . . . . . . . . X O O O O . O . . . |
$$ | . . X . . . . . . X X X X . . . . . . |
$$ | . . . , . . . . . , . . . X . , X . . |
$$ | . . . . . . . . . . . . O O X X . . . |
$$ | . . . . . . . . . . . . O X O . . . . |
$$ | . . . . . . . . . . . . O X O X . . . |
$$ | . . . . . . . . . . . . O . O O O . . |
$$ | . . . . . . . . . . . . X . . . . . . |
$$ | . . . X . . . . . , . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

-------------------------------------------------------------

However, I'l grant MW one thing: B17 - followed by my B16 and his B18 - does improve his position enough so that he has a threat that he did not have before.
The weak point on black's upper left stones is, of course, the play at 1:

Click Here To Show Diagram Code

[go]$$Wcm1 Prisoners: none
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . O . . . . . . . . . . X . . . |
$$ | . . X O . X . . . . O . . O . . . . . |
$$ | . . X , . X O . . X . . . . . X . . . |
$$ | . . . X 1 . . O X O O O X . O O X . . |
$$ | . . . . . . . . O X O X O . . X . . . |
$$ | . . . . . . . . . . X . . . . . X . . |[/go]

But prior to B17, it does not work:

Click Here To Show Diagram Code

[go]$$Wcm1 Prisoners: none
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . O . . . . . . . . . . X . . . |
$$ | . . X O 4 X . . . . O . . O . . . . . |
$$ | . . X 2 3 X O . . X . . . . . X . . . |
$$ | . . . X 1 . . O X O O O X . O O X . . |
$$ | . . . . . . . . O X O X O . . X . . . |
$$ | . . . . . . . . . . X . . . . . X . . |
$$ | . . . . . . . . . X O O O O . O . . . |[/go]

...and black win the liberties race, 4 to 3:

Click Here To Show Diagram Code

[go]$$Wcm1 Prisoners: none
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 8 O 5 O 0 . . . . . . . . . X . . . |
$$ | . . X O 4 X . . . . O . . O . . . . . |
$$ | . . X 2 3 X O . . X . . . . . X . . . |
$$ | . . . X 1 6 . O X O O O X . O O X . . |
$$ | . . . . 7 9 . . O X O X O . . X . . . |
$$ | . . . . . . . . . . X . . . . . X . . |
$$ | . . . . . . . . . X O O O O . O . . . |
$$ | . . X . . . . . . X X X X . . . . . . |
$$ | . . . , . . . . . , . . . X . , X . . |
$$ | . . . . . . . . . . . . O O X X . . . |
$$ | . . . . . . . . . . . . O X O . . . . |
$$ | . . . . . . . . . . . . O X O X . . . |
$$ | . . . . . . . . . . . . O . O O O . . |
$$ | . . . . . . . . . . . . X . . . . . . |
$$ | . . . X . . . . . , . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Once he plays in the corner, the cut works, for I would be behind on the liberties race. So I must cover the cutting point. Any of the points marked 'a' work also. But I chose the point marked with the squared stone, for there is another issue at hand.

Click Here To Show Diagram Code

[go]$$Wcm1 Prisoners: none
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . O O . O . . . . . . . . . . X . . . |
$$ | . O X O . X . . . . O . . O . . . . . |
$$ | . X X a . X O . . X . . . . . X . . . |
$$ | . . . X a a . O X O O O X . O O X . . |
$$ | . . . . . # . . O X O X O . . X . . . |
$$ | . . . . . . . . . . X . . . . . X . . |
$$ | . . . . . . . . . B O O O O . O b . . |
$$ | . . X . . . . . . B B B B . . . . . . |
$$ | . . . , . . . . . , . . . B . , B . . |
$$ | . . . . . . . . . . . . O O B B . . . |
$$ | . . . . . . . . . . . . O X O . . . . |
$$ | . . . . . . . . . . . . O X O X . . . |
$$ | . . . . . . . . . . . . O . O O O . . |
$$ | . . . . . . . . . . . . X . . . . . . |
$$ | . . . X . . . . . , . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

If white ever gets to play 'b', the group of circled stone has to seek life in the middle. The squared stone is not quite close enough for a direct connection, but it does ensure that if white pushes through, I can cut his stones off:

Click Here To Show Diagram Code

[go]$$Wcm1 Prisoners: none
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . O O . O . . . . . . . . . . X . . . |
$$ | . O X O . X . . . . O . . O . . . . . |
$$ | . X X a . X O . 3 X . . . . . X . . . |
$$ | . . . X a a . O X O O O X . O O X . . |
$$ | . . . . . # 4 . O X O X O . . X . . . |
$$ | . . . . . . 1 . 2 . X . . . . . X . . |
$$ | . . . . . . . . . B O O O O . O b . . |
$$ | . . X . . . . . . B B B B . . . . . . |
$$ | . . . , . . . . . , . . . B . , B . . |
$$ | . . . . . . . . . . . . O O B B . . . |
$$ | . . . . . . . . . . . . O X O . . . . |
$$ | . . . . . . . . . . . . O X O X . . . |
$$ | . . . . . . . . . . . . O . O O O . . |
$$ | . . . . . . . . . . . . X . . . . . . |
$$ | . . . X . . . . . , . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

...thus leaving his cutting stones far from friends and short on liberties compared to my circled stones.

Uh-oh. I may have a mistake in my analysis.

Click Here To Show Diagram Code

[go]$$Wcm1 Prisoners: none
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . O O . O . . . . . . . . . . X . . . |
$$ | . O X O . X . . . . O . . O . . . . . |
$$ | . X X a . X O . . X . . . . . X . . . |
$$ | . . . X a a . O X O O O X . O O X . . |
$$ | . . . . . # 4 . O X O X O . . X . . . |
$$ | . . . . . . 1 5 2 3 X . . . . . X . . |
$$ | . . . . . . . . . B O O O O . O b . . |
$$ | . . X . . . . . . B B B B . . . . . . |
$$ | . . . , . . . . . , . . . B . , B . . |
$$ | . . . . . . . . . . . . O O B B . . . |
$$ | . . . . . . . . . . . . O X O . . . . |
$$ | . . . . . . . . . . . . O X O X . . . |
$$ | . . . . . . . . . . . . O . O O O . . |
$$ | . . . . . . . . . . . . X . . . . . . |
$$ | . . . X . . . . . , . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

White can push through. I may have to re-think a few things.

May the devil take the hindmost.