Daijō-tennō

Daijō Tennō or Dajō Tennō (both accepted readings of 太上天皇) was the title for a Japanese Emperor who abdicated in favor of a successor. The term is often shortened to Jōkō (上皇).

As defined in the Taihō Code, although retired, a Daijō Tennō could still exert power. The first such example is the Empress Jitō in the 7th century. A retired emperor sometimes entered the Buddhist monastic community, becoming a cloistered emperor. This practice was rather common during the Heian period.

The last emperor to rule as a Jōkō was Emperor Kōkaku (1779–1817). The Emperor later created an incident called the "Songo incident" (the "respectful title incident"). The emperor disputed with the Tokugawa Shogunate about his intention to give a title of Abdicated Emperor (Daijō-tennō) to his father, who was an Imperial Prince Sukehito.

A total of 62 Japanese emperors abdicated. An incomplete list follows:

Prince Kusabake was named as crown prince to succeed Empress Jitō, but he died at a young age. Kusabake's son, Prince Karu, was then named as Jitō's successor. He eventually would become known as Emperor Monmu.

In 697, Jitō abdicated in Mommu's favor; as a retired sovereign, she took the post-reign title daijō-tennō. After this, her imperial successors who retired took the same title after abdication.

Jitō continued to hold power as a cloistered ruler, which became a persistent trend in Japanese politics. She died four years later at the age of 58.

Gemmei had initially planned to remain on the throne until her grandson might reach maturity. However, in 715, Gemmei did abdicate in favor of Mommu's older sister who then became known as Empress Genshō. Genshō was eventually succeeded by her younger brother, who then became known as Emperor Shōmu.

The Empress reigned for eight years. After abdicating, she was known as Daijō-tennō; and she was only the second woman after Empress Jitō to claim this title. Gemmei lived in retirement until her death at the age of 61.

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