Oni was a system of conferring a rank above a certain court rank to the descendants of high officials, according to the court ranks those high officials, the descendants' forefathers, had under the system of the Ritsuryo codes in Japan.
蔭位（おんい）とは、日本の律令制体制のなかで、高位者の子孫を父祖である高位者の位階に応じて一定以上の位階に叙位する制度。