China's 警衔 system (since 1992) has 5 grades and 13 levels, from 警员 (constable) up through 警司, 警督, 警监, to 总警监 (Commissioner-General). Armed police (武警) follow military ranks (军衔) instead.
memory
衔 appears in many official-rank words: 军衔 (military rank), 头衔 (job title), 官衔 (official title). Originally 衔 meant 'a horse's bit' - something held in the mouth - and extended to 'something held / borne (as a title)'.
