Emperor Kanmu (桓武天皇, Kammu-tennō; 735 – April 9, 806), or Kammu, was the 50th emperor of Japan, according to the traditional order of succession. Kammu reigned from 781 to 806, and it was during his reign that the scope of the emperor's powers reached its peak. His reign saw the transition from the Nara period to the Heian period.
Kammu's personal name (imina) was Yamabe (山部). He was the eldest son of Prince Shirakabe (later known as Emperor Kōnin), and was born prior to Shirakabe's ascension to the throne. According to the Shoku Nihongi (続日本紀), Yamabe's mother, Yamato no Niigasa (later called Takano no Niigasa), was a 10th generation descendant of Muryeong of Baekje (462–523).
After his father became emperor at the age of 61, Kammu's half-brother, Prince Osabe was appointed to the rank of crown prince. His mother was Princess Inoe, a daughter of Emperor Shōmu; but instead of Osabe, it was Kammu who was later named to succeed their father. After Inoe and Prince Osabe were confined and then died in 775, Osabe's sister – Kammu's half-sister Princess Sakahito – became Kammu's wife. Later, when he ascended to the throne in 781, Kammu appointed his young brother, Prince Sawara, whose mother was Takano no Niigasa, as crown prince. Hikami no Kawatsugu, a son of Emperor Tenmu's grandson Prince Shioyaki and Shōmu's daughter Fuwa, attempted to carry out a coup d'état in 782, but it failed and Kawatsugu and his mother were sent into exile. In 785 Sawara was expelled and died in exile.
The Nara period saw the appointment of the first shōgun, Ōtomo no Otomaro by Emperor Kammu in 794 CE. The shōgun in this time was not the type of de facto military dictator of Japan as in later history but was appointed to pacify the northern borderlands. The full title "Sei-i Taishōgun" means "Barbarian-subduing Great General". Emperor Kammu granted the second title of shōgun to Sakanoue no Tamuramaro for subduing the Emishi in northern Honshu.
Kammu had 16 empresses and consorts, and 32 imperial sons and daughters. Among them, three sons would eventually ascend to the imperial throne: Emperor Heizei, Emperor Saga and Emperor Junna. Some of his descendants (known as the Kammu Taira or Kammu Heishi) took the Taira hereditary clan title, and in later generations became prominent warriors. Examples include Taira no Masakado, Taira no Kiyomori, and (with a further surname expansion) the Hōjō clan. The waka poet Ariwara no Narihira was one of his grandsons.
Kammu is traditionally venerated at his tomb; the Imperial Household Agency designates Kashiwabara no Misasagi (柏原陵, Kashiwabara Imperial Mausoleum), in Fushimi-ku, Kyoto, as the location of Kammu's mausoleum.
Kammu was an active emperor who attempted to consolidate government hierarchies and functions. Kammu appointed Sakanoue no Tamuramaro (758–811) to lead a military expedition against the Emishi.
773: Received the title of crown prince.
April 30, 781(Ten'ō 1, 3rd day of the 4th month): In the 11th year of Kōnin's reign, he abdicated; and the succession was received by his son Kammu. Shortly thereafter, Emperor Kammu is said to have ascended to the throne. During his reign, the capital of Japan was moved from Nara (Heijō-kyō) to Nagaoka-kyō in 784. Shortly thereafter, the capital would be moved again in 794.
July 28, 782 (Enryaku 1, 14th day of the 6th month): The sadaijin Fujiwara no Uona was involved in an incident that resulted in his removal from office and exile to Kyushi. Claiming illness, Uona was permitted to return to the capital where he died; posthumously, the order of banishment was burned and his office restored. In the same general time frame, Fujiwara no Tamaro was named Udaijin. During these days in which the offices of sadaijin and udaijin were vacant, the major counselors (the dainagon) and the emperor assumed responsibilities and powers which would have been otherwise delegated.
783 (Enryaku 2, 3rd month): The udaijin Tamaro died at the age of 62 years.
783 (Enryaku 2, 7th month): Fujiwara no Korekimi became the new udaijin to replace the late Fujiwara no Tamaro.
793 (Enryaku 12): Under the leadership of Dengyō, construction began on the Enryaku Temple.
794: The capital was relocated again, this time to Heian-kyō, where the palace was named Heian no Miya (平安宮, "palace of peace/tranquility").
November 17, 794 (Enryaku 13, 21st day of the 10th month): The emperor traveled by carriage from Nara to the new capital of Heian-kyō in a grand procession. This marks the beginning of the Heian period.
794 appointed Ōtomo no Otomaro as the first Shōgun "Sei-i Taishōgun—"Barbarian-subduing Great General", together with Sakanoue no Tamuramaro subdues the Emishi in Northern Honshu.
806: Kammu died at the age of 70. Kammu's reign lasted for 25 years.
The years of Kammu's reign are more specifically identified by more than one era name (nengō).