The Origins of the Shikinen Sengu at Ise Jingu: Emperor Tenmu's Ambition

Emperor Tenmu (?-686, 天武天皇), the 40th emperor of Japan, ascended the throne after winning the Jinshin War, the largest civil conflict in ancient Japanese history. He established the Shikinen Sengu system, the ritual rebuilding of Ise Jingu (Ise Grand Shrine), a tradition that has endured for over 1,300 years. After his death, his consort, Empress Jitō, carried out the first Shikinen Sengu of Kotaijingu, known as Naiku (Inner Shrine) in 690, followed by that of Toyo’uke-no-Omikami, known as Geku (Outer Shrine) in 692.

The Shikinen Sengu

The Shikinen Sengu is held once every 20 years. On this occasion, the main sanctuaries and auxiliary buildings of both the Inner and Outer shrines are completely rebuilt. All sacred garments and ritual treasures - approximately 800 types, totaling about 1,600 items - dedicated to the deities are also newly made. These include offerings to Amaterasu Ōmikami of the Naiku, Toyo’uke-no-Omikami of Geku, and many other kami (deities). Each item is created using ancient techniques faithfully preserved, while reflecting the highest level of craftsmanship of its time by master swordsmiths, metalworkers, lacquer artisans, and textile artists.

This sacred tradition has been passed down through the ages. Preparations for the 63rd Shikinen Sengu are underway, with related festivals and rituals beginning in advance of its most important ceremony, the Sengyo-no-Gi (the ritual transfer of the deity), scheduled for the autumn of 2033. Emperor Tenmu established the Shikinen Sengu to achieve spiritual unity, bringing the people's hearts and minds together under the authority of the sun goddess.

The Crushing Defeat at the Battle and the Succession Crisis

In 663, Prince Naka-no-Ōe (later the 38th Emperor Tenji), and elder brother of Prince Ōama (later Emperor Tenmu), led a military expedition to aid Baekje on the Korean Peninsula but suffered a crushing defeat at the battle of Baekgang. Fearing a Tang-Silla invasion, he strengthened Japan’s defenses through extensive fortification projects. He later moved the capital from the vulnerable Naniwa Palace on Osaka Bay to the inland Ōtsu Palace in Ōmi Province. These measures, combined with the costs of war, increased discontent among powerful regional clans. Amid growing unrest, Emperor Tenji at first considered passing the throne to his younger brother, Prince Ōama. However, he ultimately favored his own son, the capable Prince Ōtomo, as his successor, placing Prince Ōama in a precarious position. Sensing the threat to his life, Prince Ōama withdrew to Yoshino together with his wife, Princess Uno Sarara, and their young sons, Prince Kusakabe (about ten years old) and the infant Prince Osakabe. In the cold autumn of the tenth month, they traveled some 100 kilometers along rugged mountain paths to reach Yoshino.

The Jinshin War and Prince Ōama’s Victory

After Emperor Tenji’s death, Prince Ōama raised an army. The Jinshin War soon erupted between their rival factions. Prince Ōama quickly secured the Fuwa Barrier (modern-day Sekigahara), a strategic gateway linking eastern and western Japan, thereby preventing Prince Ōtomo from mobilizing forces from the east. Supported by powerful eastern clans already dissatisfied with Emperor Tenji’s government, Prince Ōama gained the advantage.

Meanwhile, Uno Sarara and their children remained at Kuwana while he directed military operations from Fuwa. Advancing northward along Lake Biwa, Prince Ōama's forces won a series of battles against the Ōtomo faction. The final confrontation took place at the Karahashi Bridge over the Seta River near the Ōtsu Palace. Prince Ōama’s army attacked from the east while Prince Ōtomo's forces advanced from the west. Prince Ōama emerged victorious, the Ōtomo forces fled, and Prince Ōtomo took his own life.

Prince Ōama then returned to Asuka, neglecting the Ōtsu Palace, and established the Asuka Kiyomihara Palace as the new capital. He ascended the throne the following year, marking the beginning of the reign of Emperor Tenmu.

The Reforms of Emperor Tenmu and Empress Uno Sara

Upon ascending the throne, Emperor Tenmu undertook two major initiatives:
(1) the establishment of a highly developed system of governance, and
(2) the spiritual unification of the powerful clans, including those who supported his regime.

In the early 7th century, Prince Umayado (Prince Shōtoku), who built Horyuji Temple, laid the ideological foundations of imperial rule through reforms such as the Twelve Cap and Rank System and the Seventeen-Article Constitution, which emphasized governance centered on the emperor. These ideas were later developed through policies such as the Public Land and People System. Building on this accumulated framework, Emperor Tenmu established the practical foundations of a centralized state by promulgating the Asuka Kiyomihara Code. This legislative system was based on Ritsu (penal codes) and Ryo (administrative laws), forming the essential framework of the Ritsuryo state

At the same time, Emperor Tenmu sought to unite the nation spiritually. From ancient times, clans throughout Japan had revered the sun as a divine power. Emperor Tenmu defined this sun deity as Amaterasu Ōmikami, the ancestral goddess of the imperial house, enshrined her at Ise Jingu, and established her worship as a state ritual. To ensure the lasting presence of this sacred power, he instituted the Shikinen Sengu, a national ceremony in which the shrine is ritually renewed every 20 years.

Through this system, Amaterasu Ōmikami, the emperor, and the state were bound together as one. By establishing the Shikinen Sengu every 20 years, Emperor Tenmu created a lasting framework for reaffirming the spiritual unity of the nation. After he died in 686, Princess Uno Sarara (later Empress Jitō) faithfully carried forward his vision, conducting the first Shikinen Sengu four years later. The institution thus became not only a legacy of Emperor Tenmu but also a testament to the partnership of Tenmu and Jitō in shaping the spiritual foundations of the Japanese state.

Emperor Tenmu Timeline

626	Prince Nakano-Oe was born
663	The Battle of Baekgang
668	Emperor Tenji (Prince Nakano-Oe) ascended the throne
672	Jinshin War
673	Emperor Tenmu ascended the throne
686	Emperor Tenmu passed away
690	Empress Jito ascended the throne
690	The first Sikinen Sengu was held at Naiku of Ise Jingu
692	The first Sikinen Sengu was held at Geku of Ise Jingu
701	Taiho Code was completed

Recommendations to Visit

Ise Jingu Shrine & Sengukan Museum at Geku

• Access from Nagoya: 1 hour and 20 minutes from Kintetsu Nagoya Station, then get off at "Iseshi Station (伊勢市)". A 5-minute walk to Geku. Take a 10-minute bus #51 or #55 to Naiku.
• Access from Kyoto: 2 hours and 10 minutes from Kintetsu Kyoto Station, then get off at "Iseshi Station (伊勢市)". A 5-minute walk to Geku. Take a 10-minute bus #51 or #55 to Naiku.