This article is from the Go FAQ, by Morten PAHLE email@example.com with numerous contributions by others.
A ko-fight is a situation which arises due to one of the basic rules
of Go, the ko rule. In its simplest form, the ko rule states that
repetitive capture is forbidden.
If the ko has a value (i.e. if it is desirable for either party to be
able to capture and fill the ko), then a ko-fight can develop.
A basic explanation of Kos which also has several examples of kos, ko
threats and which shows a local ko fight can be found on