Princess Iitoyo 飯豊青皇女
Great Queen of Yamato (possibly)
Kitahanauchi Otsuka Kofun where she is believed to be buried.[1]
Empress of Japan (possibly)
Reign	484
Predecessor	Emperor Seinei
Successor	Emperor Kenzō
Born	Iitoyo-hime 440
Died	484
Burial	Kitahanauchi Otsuka Kofun
Posthumous name Chinese-style shigō: Princess Iitoyo (Iitoyo-hime) (飯豊青皇女) Chinese-style shigō: Empress Iitoyo (Iitoyo-tennō) (飯豊天皇) Japanese-style shigō: Oshinumi-no-iitoyo-no-ao Posthumous name, according to other tradition Empress Tsunuzashi
House	Imperial House of Japan
Father	Emperor Richū or Ichinobe no Oshiwa

Iitoyo (飯豊青皇女, 440–484) was a Japanese imperial princess and possibly empress regnant.^[a][2] She was, according to traditional legend, ruler for a short period between Emperor Seinei and Emperor Kenzō. She is referred to as "Empress [Regnant] Iitoyo" (飯豊天皇 Iitoyo-tennō) in the Fusō Ryakuki and the Honchō Kōin Jōun-roku [ja], a 12th-century and a 15th-century collection of historical texts, respectively.^[3][2]

Princess Iitoyo, like Emperor Kenzō (Prince Oke; ruled 485–487) and Emperor Ninken (Prince Ōke; ruled 488–498) is said to be descended from the 17th Emperor Richū (ruled 400–405).^[2] The exact degree of this relationship is shown differently in the earliest chronicles from the 8th century:

• According to the Kojiki of 712, Iitoyo was the younger sister of the imperial prince Ichinobe no Oshiwa and thus the daughter of Emperor Richū and aunt of the princes Ōke and Oke.
• In turn, according to the Nihon Shoki of 720, Iitoyo was the daughter of the prince and his wife Hayehime, making her the sister of Ōke and Oke and, like the two, a grandchild of Emperor Richū.

According to the chronicles mentioned, after the death of the 20th Emperor Ankō (presumably ruled 453–456), his brother murdered all rivals who could claim the throne, and then ruled as the 21st Emperor Yūryaku (presumably ruled 456–479). His victims included above all his cousin Prince Ichinobe no Oshiwa, who was the eldest son and crown prince of Emperor Richū. Oshiwa's sons Ōke and Oke fled to the province after his murder, but there is no information about their aunt (sister, according to the Nihon Shoki) Iitoyo during this time.

Iitoyo appears in the chronicles for the first time in the history of the 22nd Emperor Seinei (presumably ruled 479–484), the son and successor of Emperor Yūryaku. Seinei had no children and otherwise no close relatives. Princes Ōke and Oke were in hiding, so another suitable heir to the throne from the lineage of the Sun Goddess Amaterasu had to be sought.

According to the Kojiki, this search ended with the discovery of Princess Iitoyo at the Tsunosashi Shrine, in Oshinumi, in Kazuragi, where she conducted her political affairs.^[1] She then appears to have taken over as regent until Wodate, the governor of Harima province, sent a message to the capital after his discovery of princes Ōke and Oke. Iitoyo then gave the order to bring her nephews to her in the palace, where she presumably handed the rule over to Ōke.

The course of these events is presented somewhat differently in the Nihon Shoki. In the Nihon Shoki, two grandsons of Emperor Richū were eventually found. However, both spent a year declining the throne so it was offered to Iitoyo. So she acted as regent until one of Richū's grandsons agreed to take the throne.^[4] It is unknown if before modern scholars, she was viewed as a regent or monarch in her own right.^[2] She gave herself the title Oshinomi no Ihitoyo no Awo no Mikoto. After eleven months in the winter of the same year, she died and was buried in a burial site (misasagi) on Mount Haniguchi in Katsuraki.

After Empress Jingū, Princess Iitoyo is the second woman described in the chronicles as having governed the country for a certain period of time. But she is generally not recognized as a ruling empress by historians and she does not appear in the official list of emperors of Japan. In the 1219 Japanese historical work Gukanshō, written by the Buddhist monk Jien, Iitoyo was a reigning empress, based on the following explanation:

"Since the two brothers were unbending in deferring to each other, their young sister followed Seine on the throne as a reigning empress in the second month of the year in which Seine died. But she herself died in the 12th month of that same year. Perhaps that it is why we do not find her reign listed in the ordinary Imperial chronologies and why people know nothing at all about her. She was called Empress Iitoyo and it is said that her reign was in the kinoe-ne year of the 60-year cycle." - Jien: Gukanshō

Iitoyo's name was entered as Empress Tsunuzashi in the list of emperors by Ernest Mason Satow in the Japanese Chronological Tables (1874).

After Isaac Titsingh's translation of Nihon Ōdai Ichiran, which was written in 1625, Iitoyo was not counted among the official emperors as she had ruled for less than ten months, but she had been given a posthumous imperial name after her death (Japanese: 飯豊天皇, Empress Iitoyo). Iitoyo is also known under other posthumous names (Okurina) such as Empress Pagei and Empress Tsunuzachi. She is also recognized as a sovereign empress on various occasions, for which information can also be found in the Nihon Shoki, where the term bō is used for her death, which is otherwise reserved exclusively for emperors.

Historians have a variety of theories about her reign. According to one,^[who?] Iitoyo may be identical to Queen Taiyoo, a successor to Himiko, who ruled Yamatai. The historian Shinobu Orikuchi sees her as the first ruling empress in the history of Japan, who combines the roles of the shaman and the sovereign. Mitakō Mihoo, on the other hand, believes that Iitoyo was a rival ruler at the time of the 26th Emperor Keitai (traditionally ruled 507–531) before he became ruler of a unified Yamato. Mizuno Yū even argues that the Emperors Seinei, Kenzō, and Ninken did not exist at all, and that Iitoyo reigned after Emperor Yūryaku for 15 years.

• Kojiki → Basil Hall Chamberlain: A Translation of the “Ko-ji-ki,” or “Records of ancient matters”, Read before the Asiatic Society of Japan April 12, May 10, and June 21, 1882; Reprinted, May, 1919.
• Nihonshoki → William George Aston: Nihongi: Chronicles of Japan from the Earliest Times to AD 697, Vol. 1, London: The Japan Society 1896.
• Gukanshō → Delmer M. Brown, Ichirō Ishida: The Future and the Past: a translation and study of the Gukanshō, an interpretative history of Japan written in 1219, University of California Press 1979.
• Nihon Ōdai Ichiran → Isaac Titsingh (ed.): Nipon o daï itsi ran ou Annales des empereurs du Japon.; French translation by Hayashi Gahō: Nihon Ōdai Ichiran, 1652; Paris: Oriental Translation Fund of Great Britain and Ireland in 1834. P. 29

• Louis-Frédéric (translated by Käthe Roth): Japan Encyclopedia, Harvard University Press 2005.
• Ernest Mason Satow: Japanese Chronological Tables (et al.), Reprinted by Yedo 1874, Bristol: Ganesha 1998.
• Ben-Ami Shillony: Enigma of the Emperors: Sacred subservience in Japanese History, Global Oriental 2005.
• Joan R. Piggott: Chieftain Pairs and Corulers: Female Sovereignty in Early Japan, in: Hitomi Tonomura, Anne Walthall, Wakita Haruko (ed.): Woman and Class in Japanese History, Michigan Monograph Series in Japahese Studies, No. 25, Ann Arbor: Center for Japanese Studies, University Michigan