two-stage ko

A two-stage ko is a sequence of two linked ko fights. Once the first ko is resolved, the resulting position produces or requires a second ko fight. The two stages are therefore connected: the outcome of the first stage determines the position and the options available in the second.

During the sequence, the players alternate ko captures and ko threats through both stages. Reading a two-stage ko means assessing the combined value of the two fights rather than judging either one in isolation. The exact result depends on the position, the available ko threats, and the ko rules in use.

Unlike a simple ko, a two-stage ko has two linked stages. Unlike a double ko, its fights are generally sequentially linked rather than merely two independent kos existing at the same time. It should not be treated as equivalent to a double ko or a three-stage ko.