Their text does not contain a definition. Shape consideration leads to a reduced number of kos on the board. The rules are a model for use of disturbance rules. Complexity Complexity describes how hard it is to determine all kos on the board and all allowed moves and how long move-sequences in the game can become. Complexity is a means of worst case analysis.
Complexity mainly occurs as linear or exponential in the number of board points.
Sets only considering basic kos allow determination of all kos on the board in linear time. The Prohibition Rules have more success in this respect. Examples Many difficult examples with detailed comments are available. They are most interesting under any ruleset. Not more than in Classification and Super Ko is available yet.