Kotaishiki indicates the laws concerns the replacement of a government officer with a new officer under the Ritsuryo system (a system of centralized government based on the ritsuryo code) in Japan, matters necessary for continuing the duties of the office and how they should be handed over to the successor.
交替式（こうたいしき）は、日本の律令官吏が交替する際の事務引継ぎに関する法規集である。