Top of page

New Era, New Law Number

Share this post:

The following is a guest post by Sayuri Umeda, a foreign law specialist who covers Japan and other countries in East and Southeast Asia. Sayuri has previously written posts for In Custodia Legis on various topics, including Holy Cow – Making Sense of Japanese Wagyu Cow Export RulesJapanese Criminal Legal System as Seen Through the Carlos Ghosn CaseDisciplining Judges for “Bad Tweets”Engagement under Japanese Law and Imperial House RulesIs the Sound of Children Actually Noise?How to Boost your Medal Count in the Olympics, South Korean-Style, and many more.

A Japanese law is identified by an act number and a year, with numbers restarting each year.  The “year” is not the fiscal year, but the calendar year.  (Id.)  However, there are two kinds of calendar years in Japan: one is the year of the emperor era (gengo or gengou), and the other is the western calendar year (Gregorian calendar). A new gengo, the Reiwa era, commenced earlier this year when Emperor Naruhito assumed the throne on May 1, 2019.

The origins of gengo are found in ancient China.  A Chinese ruler introduced the era year system around 140 B.C.  However, China abolished the era year system after the Qing Dynasty.  Japan is the only country that still uses era years.

There is a law to regulate the emperor eras today in Japan: the Gengo Act (Act No. 43 of 1979).  Before World War II, gengo had a basis in the former Imperial Household Act.  However, the Allied Occupation abolished this Act.  The new Imperial Household Act (Act No. 3 of 1947) was enacted and replaced the old one on May 1, 1947, the day the Constitution of Japan took effect .  The new Act, however, did not have a provision concerning gengo.  Therefore, the gengo of that time, the Showa era, did not have any legal basis after May 1, 1947, until the 1979 Gengo Act (Act No. 43 of 1979) was enacted.

The Gengo Act is very short.  It has only two provisions:

  1. A gengo is set by a Cabinet Order.
  2. A gengo is changed only when there was succession of Emperors.

There is no provision that obliges the government or private persons to use the gengo year.  The Chief Cabinet Secretary Kan recently stated, before Reiwa took effect as the new gengo, that, while the custom of using the gengo year in public documents should be continued, private persons are free to use either the gengo year or western calendar year.

Coming back to the issue of act numbers, as a custom, the gengo year has been used for numbering acts in Japan.  However, when people abroad cite act numbers in English, we use the western year because it is assumed that non-Japanese, generally, do not know the gengo year. For example, the Blue Book (for legal citation) uses western years to cite Japanese statutes, regulations, and orders.

I did not realize that law number would restart after May 1, 2019, the first date of the Reiwa era,  until I read a news article about Cabinet notifications regarding the succession of emperors and then checked the Notifications themselves.  Cabinet notifications also started from number one on May 1, 2019.  This was not noticeable the last time that the eras changed.  The previous Heisei era started on January 8, 1989, but no law was enacted between January 1 and 7, 1989.

I further realized that there would be some laws and regulations with the same act numbers in 2019.  For example, act number 6 of 2019 (Heisei 31) is the Act to Amend Parts of the Income Tax Act and Other Acts, and act number 6 of 2019 (Reiwa 1) is the Act to Amend the Radio Act.

From now on, when I specify an act that has a law number between 1 and 20 in 2019, I must specify whether the year is in the Heisei era or Reiwa era.

Photo of new era Reiwa by flickr user MIKI Yoshihito (Apr. 3, 2019). Used under Creative Commons License.



Comments (2)

  1. Very interesting! This makes a great example of law librarianship. It’s a pretty science-y problem for library science (e.g., how do we disambiguate and catalog these same-year, same-number laws; and make them searchable with minimal confusion to the naive user?).

    I imagine there will be plenty of examples of citation error (both by practitioners (e.g., contract drafters) and in the Diet’s own amending laws) whereby they cite the wrong/unintended Act of 2019. This will be interesting to watch for statutory-/contract- construction geeks.

    • Thanks for the comment. By the way, according to Sayuri, the Diet almost never makes mistakes with their citations.

Add a Comment

Your email address will not be published. Required fields are marked *