: Ōi was not just an assistant; modern art historians widely consider her a direct co-creator and partner in Hokusai’s studio during his later decades.

: While Hokusai was famous for his dynamic lines and landscapes, Ōi was a master of Bijin-ga (paintings of beautiful women) and was lauded for her pioneering manipulation of light, shadow, and chiaroscuro.

Before it was a film, "Miss Hokusai" was a living person. Katsushika Ōi (c. 1800 – c. 1866) was the daughter of , the master printmaker behind the globally recognized The Great Wave off Kanagawa .

: She married an artist but quickly divorced him—reportedly because she laughed at his inferior art. She returned to her father's hovel to paint.