Imperial House of Japan

The founding myths link the imperial house to the kami. Amaterasu sent her grandson Ninigi down to rule the land with three sacred treasures – a mirror, a sword and a jewel – and Emperor Jinmu, his descendant, conquered Yamato. The date of 660 BCE for Jinmu's accession was calculated by later chroniclers and has no historical basis, but it was celebrated as National Foundation Day (11 February) from 1873 and, after an interruption, again from 1967.

Archaeologically, the house originated among the great kings (ōkimi) of Yamato in the Kofun period, whose enormous keyhole tombs in the Nara Basin and Osaka Plain remain designated imperial mausolea. The title tennō, 'heavenly sovereign', came into use in the late seventh century under Emperor Tenmu and Empress Jitō, together with the country name Nihon.

In the Asuka and Nara periods emperors ruled actively at the head of a Chinese-style state. From the ninth century the Fujiwara regents governed on their behalf, and from 1086 retired emperors wielded power from their cloisters. After 1185 the shogunates held military and political authority, while the court in Kyoto kept the right to confer titles, set the calendar and name eras. Attempts to restore direct imperial rule, by Go-Toba in 1221 and Go-Daigo in 1333, failed; Go-Daigo's rebellion split the dynasty into Northern and Southern Courts until 1392.

In the Edo period the court was closely supervised by the Tokugawa and its income was modest, but the emperor's symbolic authority grew as scholars of national learning idealised him. In the 1860s opponents of the shogunate rallied around the throne, and in 1868 rule was 'restored' to the sixteen-year-old Emperor Meiji.

The Meiji Restoration made the emperor the centre of the new nation. The court moved to Tokyo, Edo Castle became the Imperial Palace, and the constitution of 1889 declared the emperor 'sacred and inviolable', sovereign and supreme commander of the army and navy. Shrine Shinto was organised around the imperial cult, and the Imperial Rescript on Education of 1890 made loyalty to the throne the core of schooling. From 1868 each reign received a single era name.

In practice emperors seldom decided policy themselves, acting on the advice of ministers and elder statesmen, but their authority was invoked to justify militarism and war in the 1930s and 1940s. The extent of Emperor Shōwa's personal responsibility for the war is debated among historians; he was not indicted by the Tokyo Tribunal, and his intervention in August 1945 was decisive for Japan's surrender.

On 1 January 1946 the emperor issued a rescript rejecting the notion that he was a living god. The Constitution of Japan, in force from 3 May 1947, defines the emperor as 'the symbol of the State and of the unity of the people, deriving his position from the will of the people with whom resides sovereign power', and states that he has no powers related to government. His constitutional acts – appointing the prime minister designated by the Diet, promulgating laws, convoking the Diet, receiving ambassadors – are performed with the advice and approval of the cabinet.

The emperor and his family also perform private Shinto rituals, such as the harvest festival Niinamesai each November, visit disaster areas, support charities and represent Japan abroad. Emperor Akihito, the first to reign from the start under the postwar constitution, shaped this role through visits to former battlefields and disaster zones. He abdicated in 2019 under a special law, and his son Naruhito became emperor.

Three sacred treasures (sanshu no jingi) symbolise the emperor's legitimacy: the mirror Yata no Kagami, the sword Kusanagi no Tsurugi and the curved jewel Yasakani no Magatama. According to tradition the mirror is enshrined at the Inner Shrine of Ise, the sword at Atsuta Jingū in Nagoya, and the jewel in the Imperial Palace, with replicas of the mirror and sword kept in the palace. The regalia are never shown in public; at an accession, the sword and jewel are presented to the new emperor in covered cases.

The Imperial House Law of 1947 limits the throne to men descended in the male line. Historically, eight women reigned as empresses in their own right, in ten reigns, the last being Empress Go-Sakuramachi in the eighteenth century, but all were daughters of the male line. Women of the imperial family who marry commoners leave the imperial house.

At the start of the Reiwa era the eligible heirs were the emperor's younger brother, Crown Prince Akishino (Fumihito), his son Prince Hisahito, and the emperor's elderly uncle Prince Hitachi. The small number of heirs has prompted repeated debate on allowing female emperors or emperors descended through the female line, or on keeping female members in the imperial family after marriage.

Members of the imperial family appear on the balcony of the Chōwa-den hall at the Imperial Palace for public greetings on 2 January and on the emperor's birthday, 23 February. The palace grounds can be visited on guided tours, and the East Gardens, with the stone foundations of Edo Castle's keep, are open to the public. In Kyoto the Imperial Palace, the Katsura Imperial Villa and the Shūgakuin Imperial Villa, managed by the Imperial Household Agency, are also open to visitors.