Throw-in ko

  Difficulty: Beginner   Keywords: Ko

Throw-in moves are a common technique both to create kos - which is explained here - or to capture a ko first.

[Diagram]

Throw-in for ko

In the endgame Black can throw in at B1 and start a ko here. First Black plays B1, and White must take with W2.

[Diagram]

Continuation

Then Black plays B3 and White is in no position to connect. White has to start the ko by capturing B3. It is however hard for White to resist: large threats are required.

[Diagram]

Black's ko victory

Black has a follow-up at a which is substantial, once Black has captured to win the ko (marked stone). If White just connects at a Black has of course taken profit in sente here (and then can return to answer White's threat).

[Diagram]

No profit

Simply playing B1 here makes this area all neutral points, which is much inferior for Black.

--Charles Matthews


[Diagram]

Like a 10,000 year ko

Black makes a throw-in at B1 to make the ko. White could make the ko with a throw-in at W2. Black could also make seki by playing B2 instead of B1.

This position is like a ten thousand year ko because whoever makes the ko, the opponent takes it first, and one player can make seki.

Black can change his mind about the seki and make a ko by sacrificing three stones. See Sending Three Returning One.



This is a copy of the living page "Throw-in ko" at Sensei's Library.
(OC) 2012 the Authors, published under the OpenContent License V1.0.
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