Re: Tsumego - dead, but WHY??
Posted: Sun May 26, 2019 10:46 am
In this diagram, 
removes the last liberty of these 7 white stones. By the rule of capture, the white stones are removed from the board.
This is what we mean by Black captures the white stones.
Black kills the white stones, because their eyespace is reduced to 1 eye.
Black does not capture the white stones, because they still have two liberties. In fact ...
If next Black decides to capture the white stones, reducing their liberties to 1, the maneuver needs to go in 3 steps.
After White can capture the two stones at 
.
In the resulting position,
again goes for capture, but again White can postpone being captured, by capturing herself at 
Finally White has only one liberty left and Black :b5:captures all 7 stones, as in the very first diagram.
The whole sequence of mutual captures goes to show that Black has originally killed White, in the second diagram.
Now what did I mean with worry free?
Just like in diagram 2, Black killes White by reducing the eyespace to 1 eye. However, Black is not worry free: the black chain has 3 liberties, against White's 2 inside. Black is ahead in the capturing race but needs to be mindful of his small advantage.
When White reduces Black to 2 liberties, it's not sufficient for Black to have killed the white stones in the corner. He must set out to effectively capture them, starting with as in the above sequence of captures.
If there's anything unclear about the above, ask freely.
removes the last liberty of these 7 white stones. By the rule of capture, the white stones are removed from the board.This is what we mean by Black captures the white stones.
Black
kills the white stones, because their eyespace is reduced to 1 eye.Black
does not capture the white stones, because they still have two liberties. In fact ... If next Black decides to capture the white stones, reducing their liberties to 1, the maneuver needs to go in 3 steps.
After
White can capture the two stones at .In the resulting position,
again goes for capture, but again White can postpone being captured, by capturing herself at Finally White has only one liberty left and Black :b5:captures all 7 stones, as in the very first diagram.
The whole sequence of mutual captures goes to show that Black has originally killed White, in the second diagram.
Now what did I mean with worry free?
Just like in diagram 2, Black
killes White by reducing the eyespace to 1 eye. However, Black is not worry free: the black chain has 3 liberties, against White's 2 inside. Black is ahead in the capturing race but needs to be mindful of his small advantage.When White
reduces Black to 2 liberties, it's not sufficient for Black to have killed the white stones in the corner. He must set out to effectively capture them, starting with as in the above sequence of captures.If there's anything unclear about the above, ask freely.
never surrender ! 