Emperor Kōbun (弘文天皇) was the 39th emperor of Japan, according to the traditional order of succession. Kōbun's reign lasted only a few months in 672.

Traditional narrative

Emperor Kōbun was named the 39th emperor by the Meiji government in 1870; and since the late 19th century, he is known by the posthumous name accorded to him by Meiji scholars. In his lifetime, he was known as Prince Ōtomo (大友皇子, Ōtomo no ōji). He was the favorite son of Emperor Tenji; and he was also the first to have been accorded the title of Daijō-daijin. Now, Japanese Imperial Household Agency and minority of contemporary historians place the reign of Emperor Kōbun between the reigns of Emperor Tenji and Emperor Tenmu; but the Nihongi, the Gukanshō, the Jinnō Shōtōki and majority of contemporary historians do not recognize this reign. Prince Ōtomo was only given his posthumous title and name in 1870. The actual site of Kōbun's grave is known. This emperor is traditionally venerated at a memorial Shinto shrine (misasagi) at Shiga. The Imperial Household Agency designates this location as Kōbun's mausoleum. It is formally named Nagara no Yamasaki no misasagi.

Non-nengō period

The years of Kōbun's reign are not linked by scholars to any era or nengō. The Taika era innovation of naming time periods – nengō – languished until Mommu reasserted an imperial right by proclaiming the commencement of Taihō in 701. In this context, Brown and Ishida's translation of Gukanshō offers an explanation about the years of Empress Jitō's reign which muddies a sense of easy clarity in the pre-Taiho time-frame:

Kugyo

The top court officials (公卿) during Emperor Kōbun's reign included:

Consorts and children

Consort: Princess Tōchi (十市皇女), Emperor Tenmu's daughter Consort: Fujiwara no Mimimotoji (藤原耳面刀自), Fujiwara no Kamatari's daughter Emperor Kōbun had another son named Prince Yota (興多王), whose mother is unknown.