History Files



An Introduction to Japan

Compiled by Peter Kessler, 1999



The Imperial line of Japan was founded when a tribal band from Kyushu migrated to Honshu and took control of land there. They worshipped the sun goddess Amaterasu.

The Japanese Historical Era starts in 660 BC (AD 1999 + 660 = 2659 Anno Japoniae). In modern times the Japanese historical era, unlike the Chinese, has frequently been used for ordinary dating. Thus the famous naval fighter aircraft of World War II, the Mitsubishi A6M, was known as the "Zero" for the year in which it became operational, 2600 of the Jimmu Era (=AD 1940).

The Era is now less frequently used, in part because of unpleasant associations with Japanese totalitarianism. All emperors' names are known, but not necessarily their dates.

Heian Period

Where three dates are given, the second date represents the retirement of the emperor (or, later, the Shogun or Regent). This came to be a device by which Fujiwara ministers, starting with the Regent (Sessho) Fujiwara Yoshifusa (858-872), could exercise control over minor Emperors.

As Fujiwara power declined, retired Emperors, who had become monks, began to exercise influence from their monasteries. This became the institution of the "Cloistered Emperors." Such emperors were known by the title "In," hence, Shirakawa In - who himself was the first to assume authority in this way, in 1086.

The names of Cloistered Emperors are given in coloured type, as are the dates of their assumption of Cloistered power. Usually this is identical to the dates of their retirement, but sometimes there is a delay between retirement and the assumption of Cloistered power (eg. Toba). There may also be a second retirement date.

Go-Toba was the last effective Cloistered Emperor. His second retirement was forced after his abortive attack on the Hojo Regent Yoshitoki, the Jokyu War, in 1221. He was exiled for the rest of his life to the remote Oki Islands, where, among other things, he worked on forging a sword.


This was to replace the sword of the Imperial Regalia that had been lost at sea, with the child Emperor Antoku, in the battle of Dan-no-ura. He also intended to use it to kill the Hojos, something which he never achieved.

Later in Japanese history, it became common for many figures, Regents and Shoguns as well as Emperors, to retire from office but sometimes to continue exercising much of their previous power.

A dramatic exception to that practice was when the Emperor Go-Daigo refused to accept retirement in 1331. Instead, he organised a rebellion against the Hojos and succeeded in overthrowing them in 1333. However, he was then betrayed in 1336 by the Ashikagas, who, like the Hojos, installed their own counter-emperor.

Go-Daigo and three successors were able to hold out in Yoshino and elsewhere against the Ashikagas until 1392. Although Go-Daigo's line was then accepted as legitimate, it was the Ashikaga counter-emperor who was installed (Go-Komatsu), and an agreement to alternate between the two lines was never honoured.

End of the Tairas

The Heian Period ends with the naval battle of Dan-no-ura in 1185. The Taira (or Heike) Clan had dominated the Court under Kiyomori (1118-1181), but the Minamoto (or Genji) Clan overwhelmed them after his death.

The leader of the Minamotos was Yoritomo (1147-1199), who became the first Kamakura Shogun; but it was his brother, Yoshitsune (1159-1189), who commanded the Minamoto forces and who destroyed the Tairas at Dan-no-ura.

The battle ended with one of the most dramatic and poignant moments in world history. Kiyomori's widow, Nii-no-ama, with her grandson, the seven-year-old Emperor Antoku, decided to leap into the sea, carrying the Imperial Regalia with them, rather than be taken by their enemies. (The scene is recounted in the epic Heike-Monogatari and hauntingly portrayed in Masaki Kobayashi's feature film Shin Heike Monogatari (1964).)



Text copyright P L Kessler. An original feature for the History Files.