By the way, although it was called 'kotaishiki' (indicating a kind of 'shiki') from the time it was enforced for the first time, there is also the following opinion: According to the concept of 'kyakushiki' (kyaku indicates supplementary laws or regulations, and shiki indicates detailed rules for enforcing them) in the Ritsuryo laws, use of 'kyaku' is more appropriate.
なお、施行当時より慣例的に「交替式」と呼ばれてきているが、律令法における格式のおける考え方からすれば、これは「格」にあたるのではないかとする意見もある。