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BeginnerExercise18
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Beginner Exercise 18 Solution
  Difficulty: Beginner   Keywords: Problem

Analysis

[Diagram]
Analysis

If White is allowed to capture simply at W1, Black dies.


[Diagram]
Analysis

Since White a will atari the BC stones, B2 will be neccessary sooner or later, after which W3 connects and kills Black by either almost filling into farmer's hat or bulky five (with a White stone at b).



Solution

[Diagram]
Solution

For Black so save himself, Black must not allow White to play both W1 and W3 in the analysis diagrams. The only way is to fight the ko with B1. If Black wins this ko, he lives by playing at a.




Scartol: Should I leave these so that actual beginners can have a crack at them?

[Diagram]
Black first to salvage the situation

Okay, it looks like the best black can do is get a ko. White has to fight it; white connecting at A only leads to black life at B.

Would it work better if black goes at B?


[Diagram]
Scartol is stupid

This was my initial response, but I realized (after I posted it -- stupid!) that white can connect after capturing the marked stone, and black is left with a dead shape once he captures the white stones.


[Diagram]
Black dies anyway...no answer?

Leads to bulky five and black dies. -Xelloss



[Diagram]
Black to live

This is the vital point I think. Once Black moves here, White can't play at 'a' because of a Black snapback, and can't play at 'b' because it's lacking a liberty. Black can form two eyes and live by playing at 1.


[Diagram]
If White plays at 'a'...

Black can respond with 1. Once Black moves to 1, if White tries to move to 'a', Black can capture White's stones by playing above at 'b'. If White chooses to respond at 'b' instead and capture the marked stone, Black can snapback and capture White.


[Diagram]
If White plays at 'b'...

If White plays at 'b' instead, Black can respond at 1, forcing White to capture at 2, then Black can play at 3. White is missing the liberty needed to capture Black. When Black plays at 3, White will have no choice but to use the move as sente. Black doesn't need to play there unless White tries to play at 'a' or 'b', in which case Black can simply capture the group of White stones.


[Diagram]
Dead

unkx80: After W2, Black is dead.


[Diagram]
Dead

The reason is because if B3, then W4 connects and even if Black plays at a, Black still dies in a bulky five nakade.



[Diagram]
Alive?

Now W can close ko, making B take a. If B takes over ko, he lives. In other case, W closes ko, B plays a. If then W takes c, B extends to the right, and if W doesn't play c, white can take it, close it and live



[Diagram]
Black first to salvage the situation.

B1 is the vital point. Variations lead to life for Black.


[Diagram]
Black first to salvage the situation.

unkx80: What happens after W2?



[Diagram]
Black survives.

Here, the twisted four lives.

unkx80: Thanks to the kamikaze of W4, Black lives, but White could just tenuki after B3 and Black will still be dead with a bent three.



[Diagram]
Black first to salvage the situation.

After B1, White can play for ko or seki but cannot kill.

unkx80: W2 captures, Black dies.





This is a copy of the living page "Beginner Exercise 18 Solution" at Sensei's Library.
(OC) 2004 the Authors, published under the OpenContent License V1.0.