Multi-stage ko

  Difficulty: Intermediate   Keywords: Ko

Chinese: 套劫 (to ji)
Japanese: -
Korean: -

A multi-stage ko is a special ko fight, where taking the ko produces another ko mouth. This new ko can then be fought, and this may continue for several stages. A multi-stage ko is also known as an iterated ko or dan ko in Japanese. In the past, a two stage ko was sometimes called a "two step ko" in English.

In a multi-stage ko, the fighting shifts from one ko mouth to another, so that when the original underdog takes the next ko, the opponent is taken one ko fight away from winning the whole ordeal. In a two stage ko that means that the opponent becomes the new underdog.

Contrast this with an approach ko, where all the fighting is done at the same ko mouth, and the best that can happen to the underdog is that the ko turns in to a direct one.

Two Stage Ko

Chinese: 两手劫 (liǎng shǒu ji)
Japanese: 二段劫 (nidan-kou)
Korean: 이단패 (idan-pae)

In a two-stage ko taking the ko produces another ko mouth, which must be taken before winning the ko. Example:

Two-stage ko  

In a two-stage ko the total number of successive moves needed by Black to win the ko, plus the same for White, is constant and equals 4. For instance in the above diagram Black needs 3 moves to win the ko, and White needs 1, so we get 3 + 1 = 4.

Another example

in the corner  

See also:

Three Stage Ko

Chinese: 三手劫 (sān shǒu ji)
Japanese: -
Korean: -

3-stage ko  

Here is a simple three-stage ko.

In principle, there can be very long multi-stage kos, but it is rare to see one longer than three stages in an actual game.

See also Counting A Three Stage Ko.

Multi-stage ko last edited by Malcolm on February 14, 2022 - 11:13
RecentChanges · StartingPoints · About
Edit page ·Search · Related · Page info · Latest diff
[Welcome to Sensei's Library!]
Search position
Page history
Latest page diff
Partner sites:
Go Teaching Ladder
Login / Prefs
Sensei's Library