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Strange Things Happen At The One Two Point
Path: GoProverbs   · Prev: DoorGroup   · Next: EyesWinSemeais
   

2-1 points have some particularities, even singularities and the heuristic rules of fight, learnt at the sides far from the corner, often don't apply here.

One of the reasons is the impossibility to approach from the corner side. This gives the side that occupies the 2-1 point additional tempo to win a semeai.

[Diagram]
Diag.: Usual way to fight a semeai: black wins.

[Diagram]
Diag.: Take 2-1 point first. White wins.

Now black cannot attack from either side because of damezumari.



Another feature of 2-1 point is a possibity of a throw in tesuji. One of the examples is considered in StupidMoves. I will show another example.

[Diagram]
Diag.: White 2 was a small mistake

Black played 1 as a ko-threat. I will not discuss if this was the best threat. White answered 2 giving black another threat at 'a'. White should have played at 'a'.


[Diagram]
Diag.: Marked white stone attacks marked black as well as a direct atari.

Throw in 1 (2-1 point) captures black marked stone because of a weakness at a. Actually I can point to a stupid white that lost that ko because of this mistake. It was a certain HolIgor (IGS 5k*).

 Thank you for correcting a mistake.


2-1 point is a place where a lot of ko happen. For example that ko that HolIgor (IGS 5k*) lost.

[Diagram]
Diag.: Blacks starts ko.

Black plays 1 in hope for white's mistake. White sees ko, white suspects that he wins the semeai without ko (but it is that difficult to read 8 moves ahead, shame on him!), so he decides to fight the ko.

But a sad story of white's mistake has little to do with the topic, and the topic of the page is 2-1 point. Taking it black got a ko, that saved his group.



2-1 point is a critical point of many life and death problems. The difference of living or dying locally is at least 20 points. It is something that cannot be taken easily. That's the difference between winning and losing or losing and losing badly.

Examples




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