Dates in Japanese Era Names in Unicode Standard

Martin J. Dürst duerst at
Thu Sep 29 05:45:54 CDT 2016

Just a few not very closely related comments:

On 2016/09/29 19:06, Philippe Verdy wrote:
> Is it possible that these eras start at midday instead of noon ? This could
> explain the date difference, if you do not set the time in your query (your
> query will assume a default time at 00:00 midnight)

It's extremely difficult to imagine this for Japan in this day and age.

I was in Japan when the era changed from Showa to Heisei. I remember the 
announcement very well, but I don't remember anything about the exact 
time of the cutover.

> Many people still count the second half of the night after midnight as part
> of the previous day (and so will say "Saturday evening"/"Saturday night"
> even if it's already the first hours of Sunday).

In Japan, that happens e.g. in displays of restaurants and bars, which 
may announce their opening hours as 17:30-27:00 (i.e. open until three 
in the morning the next day). But that's only a convention for 
convenience, everybody knows that it's already the next day on the calendar.

> If you test dates and don't want to specify hours, it is highly recommended
> to set the default time at midday. For the Japanese eras, it's not clear at
> which time they really start, except for the last two eras since WW2 but
> setting time at midday shoudl give the correct result. However there's no
> ambiguity during the day of era switch, if the era is correctly specified
> (and not just the year number in era).

Yes indeed. These days, people just refer to 1989 (and any dates in it) 
as Heisei 1 (平成元年). This is all the easier because otherwise, an 
exception would be necesary for only 7 days.

On the other hand, I saw places that said Showa 64 as late as July (that 
was when I climbed Mt. Fuji; a placard put up the year before said 
"closed until July Showa 64"). I also got some money in February or so 
that year and had to sign a receipt that said Showa 64 because it was 
printed earlier.

The Japanese Wikipedia article, at the bottom of the 改元 
(平成#.E6.94.B9.E5.85.83) section, says that 
in contrast to the two earlier changes in era, the change started on the 
next day, in order to give engineers time for the change. That next day 
was a Sunday, which meant that in effect, they had even more time, 
because most systems had to work with the new ear only from Monday. But 
I guess it must have been a busy weekend for those involved, anyway.

To know all the details, the best thing to do would be to check the 
official government documents, which should be available online. But I 
wouldn't be surprised if they were not specifying things to the second.

Regards,    Martin.

> 2016-09-29 5:13 GMT+02:00 Junichi Chiba <junichi.chiba.bps at>:
>> Dear all,
>> Nice to e-meet you.
>> I'm looking at the latest Unicode Standard [1] listing the dates for
>> Japanese Era Names in Table 22-8.
>> What I noticed is the begin and end dates for each era.
>> They seem to have one day difference with the dates that are recognized
>> publicly in Japan.
>> For example, the current Heisei actually started January 8th, 1989, after
>> Showa ended on 7th, 1989.
>> However, the Unicode Standard says in Table 22-8:
>> U+337B square era name heisei 1989-01-07 to present day
>> U+337C square era name syouwa 1926-12-24 to 1989-01-06
>> Looking at Wikipedia in Japanese [2] and English [3], you can see exact
>> dates for Syouwa end and Heisei start.
>> Could there be certain intentions to leave some difference in this
>> description and official dates?
>> Is the date counted according to GMT, instead of local date/time for some
>> reason?
>> [1]
>> [2]
>>> 1989年(昭和64年)1月7日に昭和天皇が崩御して、皇太子明仁親王が即位した(今上天皇)。これを受け、元号法に基づき1989年(昭和64年)
>> 1月7日に元号法に基づき改元の政令がだされ、「平成元年1月8日」と改元がなされた。
>> [3]
>>> Thus, 1989 corresponds to Shōwa 64 until 7 January and Heisei 1 ...
>> since 8 January.
>>> On 7 January 1989, at 07:55 JST, the Grand Steward of Japan's Imperial
>> Household Agency, Shōichi Fujimori, announced Emperor Hirohito's death,...
>>> The Heisei era went into effect immediately upon the day after Emperor
>> Akihito's succession to the throne on 7 January 1989.

Martin J. Dürst
Department of Intelligent Information Technology
Collegue of Science and Engineering
Aoyama Gakuin University
Fuchinobe 5-1-10, Chuo-ku, Sagamihara
252-5258 Japan

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