Provinces were ranked according to their size, as taikoku, jokoku, chukoku and gekoku, and were governed by different officials so that, for example, chukoku would not have a suke and gekoku would not have a jo, but the size classification criteria are unknown.
国にも大・上・中・下の四等級があり、中国には介がなく、下国にはさらに掾も置かれないなど、職員の異同があるが、等級区分の基準はつまびらかではない。