Japanese Era Names: Dating Objects by Nengō

Japanese boxes, certificates, prints and documents are usually dated by era name, nengō, rather than by the Western calendar. Each era begins with a new emperor, or in earlier centuries with an auspicious event, and years are counted from its start. Knowing the eras turns an inscription such as 昭和三十年 into a date you can use: 1955.

Modern eras

The first year of an era is written gannen, 元年, rather than year one. Because eras change partway through a calendar year, the first and last years overlap: Shōwa 64 and Heisei 1 are both 1989.

Late Edo eras

Before 1868, eras were shorter. These are the ones you are most likely to meet on objects of the late Edo period.

Reading a date on a box

• Dates are often written in traditional numerals, sometimes in formal forms such as 拾 for ten. Our page on numerals and dates on boxes explains them.
• Instead of a month and day, an inscription may simply say 吉日, an auspicious day, or name a season.
• Some inscriptions use the sixty-year cycle of the zodiac rather than an era name. See the Japanese zodiac and calendar.
• Certificates and receipts from the Shōwa and Heisei eras often use era years even when the object itself is Western-made.

Why it matters

A date on a box tells you when the inscription was written, not necessarily when the object was made. Artists often signed boxes years after making a piece, and later owners added boxes to older objects. Read the date as one piece of evidence alongside style, materials and condition.

Related references

• Glossary of Box Inscriptions
• Authenticating Japanese Art and Collections
• All Collector Guides