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BeginnerExercise111

 

Beginner Exercise 111 Attempts
  Difficulty: Beginner   Keywords: Problem

Jan: This is a fun problem! Since I'm not a real beginner anymore, I'll just put my guess up: White can kill, Black can live. The first statement is obvious (to me at least), the second requires more thought. I'll let others write down the details :-)

Grauniad: I'll have a go (sic):

[Diagram]
Black can live

Black 1 is the key.

If White 2 at 3, then Black 3 at 2 followed by 5 at 1 lives. Even if White 4 at 1 - suicide - were allowed, then Black 5 at 1 lives.

If White 2 is tenuki, Black 3 at 2 lives immediately.

ChrisSchack White's best sequence looks to be White 2 at 3, because a ko-threat can be played at 4.


[Diagram]
Black can live (2)

Following the sequence shown in the above diagram, a and b are miai to live.
Jan: Indeed, that's what I had in mind.

[Diagram]
Black can live

Black 1 is atari, White 2 captures and after Black 3 White can't connect (it's oshitsubushi, Charles). Maybe I'm being dense, ChrisSchack, but I see no ko :-)

ChrisSchack I just came back, looked at what I said, and thought "What was I thinking!?" ... figured out what I was thinking. Black plays a non-local ko-threat, if one is available. It's no sure thing, it depends on board position elsewhere, but it's a possibility.

Jan: With these kind of problems, there is no ko, only in your mind... (just like in the Matrix). I know what you're up against, just play a few kos and you'll see that ko is not that important. At least, when I lose, I tend not to lose by waypof a ko, And when I win it surely isn't by skilllful ko-play |-)

unkx80: Excellent answers. =)

Now I ask, when White plays first, how does White kill the group?

Grauniad: Easy. In brief: White 1 at 1 in first diagram, forming a SquaredFour. If captured, moving in this square prevents Black from forming two eyes. If not captured, threaten to capture Black directly by forming a BulkyFive at 2 (or 3), which also kills Black.

Jasonred : Is that better, or just tenuki or fill up outside liberites? Come to think of it, as soon as you play Black 1, the stones are dead, so tenuki like heck?

ChrisSchack Once the Squared Four is made, it will keep until Black kills it AND plays within it, so sure...





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