Beginner Exercise 45 / Discussion

Table of contents
White first

Black first
Table of diagrams
White is independently alive
Failure: Seki
Failure: Ko
No capture without ko
White is dead
White is dead again
Failure: Seki

[edit]

White first

ChrisSchack: White first, I guess . . . the easy case. White lives in gote, one eye to none, with 9 points.

Robert Pauli: In real life, should be spared as a ko threat.

AdamMarquis: Since it is a beginner exercise, should this case not also be pointed out? Black's descent to the edge after White takes the throw-in makes it so that White can't approach. The result is seki (with a sending-two-returning-one option for White).

However, White can patch up by not taking and make a ko - a bit risky though.

What if black takes though? Won't black have killed white without ko? -Ned G.

Brent: Well, in that case it would simply be a ko that Black didn't fight. (= If Black captures , then yes, Black wins the ko and kills White. But in compensation White gets to move twice somewhere else on the board -- once after and once after Black captures with . See ko fights for a more detailed explanation.

Bill: Don't be confused by the diagram. Black cannot take ( below) without taking the ko.

No capture without ko

[edit]

Black first

White just doesn't have the liberties needed anymore. (See next variant for at .) This is 21 points for Black in gote.^[1] This seems big enough for either player not wanting to wait . . . but should wait, it's a big ko threat.

Confused: Here is the variant, White's still dead. White can't play at a because of a shortage of liberties.

Robert Pauli: This nice seki results should Black start with hane, blindly following the proverb "the opponent's vital point is my vital point".

It features

an one-sided dame for Black (at )
a sending-two-returning-one option for Black (to the right of )
a sacrifice option for Black (filling both 2-1's and restoring seki via 2-2)

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Go to Beginner Exercise 46

[1] The play is worth 15 points by miai counting.

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Beginner Exercise 45 / Discussion last edited by HermanHiddema on May 17, 2009 - 22:27

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