Imperial China ran on the
九品官阶 (Nine-Rank System), introduced under Cao Wei in the 3rd century and refined through the Tang. Each rank was further split into
正 (principal) and
从 (associate), giving eighteen tiers from
正一品 down to
从九品. The system shaped salary, office furniture, robe color, and which gate you entered the palace by.
官阶 still describes any modern hierarchical official ladder, military or civil.
