Japanese calendar

10 Yan (Japan, 2002). Five hieroglyphs below denomination are date: Heisei 14 = 2002.

In spite of usage of Gregorian calendar nowadays, before 1873 in Japan specific Japanese calendar was used. However on coins, banknotes issue years are still marked in Japanese.

Main peculiarity of Japanese calendar: it is divided on eras of Japanese emperor's reign. For example year 1980 is equal to year 55 of Syowa (Shōwa) era; year 2008 is equal to year 20 of Heisei era.

Date structure

First of all we have to analyze a structure of the Japanese year printed on coins or banknotes:

1 — era name (on given image: Heisei);
2 — year of coin within era (on the image: 14);
3 — "nen": year of reign.

Please note that on old coins right-to-left direction of hieroglyphs can be. The simple way to detect direction of writing: just find "Nen" hieroglyph (#3 on scheme). It is always placed in the end of writing.

Era name (nengō)

As mentioned above, every Japanese era is started at the beginning of the reign of next emperor. So we need to know an exact name of era with its starting year. Following table will help us to do it:

Hieroglyphs	Name of the era	Start of reign	Comments
	明治 — Meiji	1868	"Enlightened Rule" Information in Wikipedia
	大正 — Taishō	1912	"Great Righteousness" Information in Wikipedia
	昭和 — Shōwa	1926	"Brilliant Harmony" Information in Wikipedia
	平成 — Heisei	1989	"Achieving Peace" Information in Wikipedia

Complete list of emperors you can see in Wikipedia.

So as result of this step we know year of era start. For our example (see first image or scheme) it is Heisei, so era starts in 1989.

Year within era

Next step is identifying of year within Japanese era. Sometimes on modern coins of high value year within era is written with usage of Arabic digits, but in other cases we need to translate Japanese digits into Arabic. Look at the table below, there are Japanese hieroglyphs used for indication of year:

Hieroglyph	Name	Value		Hieroglyph	Name	Value
	元 — Gan	First			六 — Roku	6
	一 — Iti	1			七 — Siti	7
	二 — Ni	2			八 — Hati	8
	三 — San	3			九 — Ku	9
	四 — Si	4			十 — Zyu	10
	五 — Go	5			百 — Hyaku	100

Several nuances you should know about:

1. First year of era can be written with 2 variants: hieroglyph "Gan" or hieroglyph "Iti".
2. If before 10 (zyu) or 100 (hyaku) is standing hieroglyph for digit 1—9, this means corresponding number of tens or hundreds.

   For example:

   = 14
   = 4 × 10 = 40
   = 4 × 10 + 4 = 44

In our example on the topmost image year is equal to 14.

Resulting calculations

This is simple. We just need to add year within era to era's starting year and then substract 1, because the start of the era is a first year, not zero.

So, in our example it is 1989 + 14 - 1 = 2002.

Is it too difficult? Sometimes on coins/banknotes both Japanese and Gregorian years printed.

Japanese year conversion