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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.

Character(s) 大 日 本 日 本 国
Rōmaji Nen Dai Nippon Nippon-koku En Sen Rin
English Year Great Japan State of Japan Yen Sen
(1/100 Yen)
Rin
(1/1000 Yen)

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.

Characters 明 治 大 正 昭 和 平 成
Era Name Meiji Taishō Shōwa
(Hirohito)
Heisei
(Akihito)
First Year
of Reign
1868 1912 1926 1989

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.

First 1 2 3 4 5 6 7 8 9 10

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.

Characters Translation Conversion
明 治 元 年 Meiji 1st
(L-R)
Meiji = 1868
1868 - 1 + 1 = AD1868
年 五 十 正 大 Taishō (10 + 5 =) 15
(R-L)
Taishō = 1912
1912 - 1 + 15 = AD1926
昭 和 三 十 六 年 Shōwa (3 x 10 + 6 =) 36
(L-R)
Shōwa = 1926
1926 - 1 + 36 = AD1961
平 成 2 2 年 Heisei 22
(L-R)
Heisei = 1989
1989 - 1 + 22 = AD2010