Beginner Exercise 211 / Solution

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Black lives.  

B1 is the vital point. Now a and b are miai.

Continuation 1  

If W2, B3 lives with a bent four.

Continuation 2.  

If W2 here, Black captures with B3...

White throw-in...  

...and if White throws in, Black captures and then a and b are miai to make two eyes.

White throw-in...  

Bill: And if B2 connects?

Brent: Oh, right. B2 is much better, thanks!

From this last variation, it looks as though Black can only expect two points of territory[1], although of course he captures more white stones as well...?

Black failure.  

If White is allowed to play W2 (it really doesn't matter where Black plays first), then White almost fills with a bulky five and Black is dead.

[1] Bill: 3.5 points of territory plus 4 captured stones.

Black lives (2)  

For extra credit, why is it only 3.5 points of territory and not 4?

(Why did White play W2? Because we assume that the outside is White territory. W2 saves 1 point.)

Extra credit answer?  

Brent: I'm still not sure about miai counting, fractional points, etc. But I'm guessing the answer is that a play at a is worth one point in gote, hence 0.5 in miai counting. (right?) If Black at a, then Black has one connected group surrounding a bent four -- hence four points. If White at a, then Black will eventually have to defend at b (probably after White c which is now sente), and Black only gets 3 points.

Is this at all correct? Even if it is, did I describe it correctly? Please teach me... (=

unkx80: For me I will accept this, but I will leave it to the endgame expert to have the final say... LoL. =P

Ko threats  

Bill: Right you are, Brent! :-)

If Black plays at black+circle, he will have 4 points, while if White plays there, Black will have only 3 points. After white+circle, Black will either have to protect with B1, or White has two ko threats with W1 - B2 and W5 - B6.

Since this is a gote position, we count Black's territory as the average, 3.5 points.

Brent: I get it, thanks!

Beginner Exercise 211 / Solution last edited by P7A77 on February 7, 2005 - 22:27
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