News Navigator: What is an era name?

The Mainichi Shimbun answers some common questions readers may have about era names, following the April 1 announcement of the new era name Reiwa, which is set to be officially implemented on May 1 when Crown Prince Naruhito succeeds to the Imperial Throne following his father Emperor Akihito's abdication the day before.

Question: Is there a set rule on how Chinese characters are chosen for an era name?

Answer: Basically, two Chinese characters with auspicious meanings are combined to make a name containing a wish for a better world. In Japan, 72 Chinese characters had been used in 247 era names until the current era name Heisei. The character "ei" was used a record 29 times, followed by the characters "gen" and "ten," each used 27 times. Eighteen other characters were used at least 10 times. Meanwhile, 30 characters have been used only once. The character "sei" was used for the first time in the era name Heisei.

Q: How was the era name Heisei devised?

A: Era names originate from entries in Chinese classical literature. The name Heisei is attributed to entries in the Book of Documents -- China's oldest written work on history -- and the famous Chinese classics Records of the Grand Historian, and represents wishes for peace in heaven and on Earth as well as in Japan and overseas.

Q: Why do era names derive from Chinese classics?

A: Japanese era names derive from Chinese classics, apparently because the era system was first adopted in China, the birthplace of Chinese characters. Emperor Wu of Han, the seventh emperor of the Hang Dynasty, first began to use the era name Jianyuan, one year after he came into rule in 141 B.C. Era names indicated the belief that emperors controlled time, and a new name was chosen every time a new emperor took over in principle. Era names were also changed to reset the atmosphere when it deteriorated due to disasters and other bad events.

Q: Why did Japan introduce the era system?

A: Japan started using era names in 645 at a time when Chinese systems were introduced here one after another amid a concentration of power in the Imperial Court. The first ever Japanese era name was Taika, famous for the Taika Reforms that occurred in 645. Tenbyokanpo, the reading used in "Nihon Nengoshi Daijiten" (An account of the creation of the names for Imperial eras in Japan), followed by four other era names in the 8th century all used four Chinese characters as exceptions, but were unpopular.

(Japanese original by Takenori Noguchi, Political News Department)