Emperor Tenji

Emperor Tenji (天智天皇, Tenji-tennō; 626 – January 7, 672), known first as Prince Katsuragi (葛城皇子, Katsuragi no Ōji) and later as Prince Nakano Ōe (中大兄皇子, Nakano Ōe no Ōji) until his accession, was the 38th emperor of Japan who reigned from 668 to 671. He was the son of Emperor Jomei and Empress Kōgyoku (Empress Saimei), and his children included Empress Jitō, Empress Genmei, and Emperor Kōbun.

In 645, Tenji and Fujiwara no Kamatari defeated Soga no Emishi and Soga no Iruka. He established a new government and carried out political reforms. He then assumed real political power as the crown prince of both Emperor Kōtoku and Empress Saimei. Despite the death of Empress Saimei, he did not accede to the throne for seven years, and came to the throne only after the relocation of the capital to Ōmi in 668. He created Japan's first family register, the Kōgo Nenjaku, and the first code of law, the Ōmi Code.

Tenji was the son of Emperor Jomei, but was preceded as ruler by his mother Empress Saimei.

Prior to his accession, he was known as Prince Naka-no-Ōe (中大兄皇子, Naka-no-Ōe no Ōji).

As prince, Naka no Ōe played a crucial role in ending the near-total control the Soga clan had over the imperial family. In 644, seeing the Soga continue to gain power, he conspired with Nakatomi no Kamatari and Soga no Kurayamada no Ishikawa no Maro to assassinate Soga no Iruka in what has come to be known as the Isshi Incident. Although the assassination did not go exactly as planned, Iruka was killed, and his father and predecessor, Soga no Emishi, committed suicide soon after. Following the Isshi Incident, Iruka's adherents dispersed largely without a fight, and Naka no Ōe was named heir apparent. He also married the daughter of his ally Soga no Kurayamada, thus ensuring that a significant portion of the Soga clan's power was on his side.

Naka no Ōe reigned as Emperor Tenji from 661 to 672.

Tenji was particularly active in improving the military institutions established during the Taika Reforms.

Following his death in 672, there ensued a succession dispute between his fourteen children (many by different mothers). In the end, he was succeeded by his son, Prince Ōtomo, also known as Emperor Kōbun, then by Tenji's brother Prince Ōama, also known as Emperor Tenmu. Almost one hundred years after Tenji's death, the throne passed to his grandson Emperor Kōnin.