Date Systems: Japan

This article contains Japanese text. Without proper rendering support, you may see question marks, boxes, or other symbols instead of kanji and kana.

Modern Japanese coins are dated using the nengō system, which specifies the era name (emperor's reign) and year of the reign.

Step 1

Determine the direction of the text by finding the character for the word "year" (see table below). If the character is right of the text, then you will read the characters from left to right. If the character is left of the text, read from right to left. Take note of the other characters commonly on Japanese coins.

Step 2

Using the table below, find the era name characters on the coin, and use the corresponding year for the next step. Keep in mind these may be reversed if the date is written from right to left.

Step 3

Using the table below, locate a series of "normal" Chinese numerals between the era name and "year" characters. If the coin has Arabic numerals instead, proceed to Step 4 and skip the calculation.

Step 4

Similar to Ethiopia, the year can be calculated from the numbers found in Step 3 by the following rule: If a number is followed by a smaller number, add. If a number is followed by a larger number, multiply. This number represents the year of the reign. Since the first year is year 1 and not year 0, you must subtract 1 before adding the number to the year found in Step 2 to get the Gregorian year. See the examples below.