Sei Shōnagon's actual given name is not known. It was the custom among aristocrats in those days to call a court lady by a nickname taken from a court office belonging to her father or husband.[1] Sei (清) derives from her father's family name "Kiyohara" (the native Japanese reading of the first character is kiyo, while the Sino-Japanese reading is sei), while Shōnagon (少納言, "lesser councilor of state") refers to a government post.[1] Her relationship to this post is unknown, though—neither her father nor either of her two husbands held such a post.[1] Bun'ei Tsunoda has suggested that it may have belonged to a third husband, perhaps Fujiwara no Nobuyoshi.[2]