Invalid dates in Japanese eras?

[Kip Cole]

Indeed I couldn’t find anything about the era definitions in TR35 either.

I’m currently interpreting “related Gregorian year” as the “the Gregorian year of the date when converted to the Gregorian calendar”.

`cyclic year` seems the least ambiguous.

`y` (calendar year) is actually also a little ambiguous to me. In a lunisolar calendar is that the cyclic year?  The cycle and year? The elapsed years since epoch?  Do you have a view?  

I can see now that different calendar era dates have some in Gregorian dates (Chinese, Korean epochs), some Julian dates (Ethiopian, Coptic epochs) and with Japanese - well it looks like some years in Julian, some in Gregorian and months/days lunisolar as you indicated.

Nothing boring about calendars!

Cheers, —Kip

Sent from my iPad

> On 9 Sep 2021, at 11:07 am, Wáng Yifán <747.neutron at gmail.com> wrote:
> 
> Hi,
> 
>> Wikipedia:  Shōhō 正保 -> (Kanei December 16, 21, January 13, 1645, Julian year)
>> CLDR: <era type="199" start="1644-12-16"/>
>> 
>> Which suggest that either Wikipedia or CLDR have the wrong year for this era? The lunisolar months and days line up but the year is different.
> 
> Now it becomes mysterious. The year number resembles that of the
> Gregorian epoch but not technically so.
> 
> I bumped into the following passage on TR #35 in the description of
> format patterns:
> https://unicode.org/reports/tr35/tr35-dates.html#dfst-year
> -----
> Related Gregorian year (numeric). For non-Gregorian calendars, this
> corresponds to the extended Gregorian year in which the calendar’s
> year begins. Related Gregorian years are often displayed, for example,
> when formatting dates in the Japanese calendar — e.g.
> “2012(平成24)年1月15日” — or in the Chinese calendar — e.g. “2012壬辰年腊月初四”.
> The related Gregorian year is usually displayed using the "latn"
> numbering system, regardless of what numbering systems may be used for
> other parts of the formatted date.
> -----
> This might be what it is supposed to, though I couldn't find the exact
> definition of "extended Gregorian year" elsewhere.
> 
> 
> 2021年9月8日(水) 21:16 Kip Cole <kipcole9 at gmail.com>:
>> 
>> Thanks very much, that definitely helps.  There are 4 “errors” that I found and since the other eras (at least for the Persian, and very ironically the Chinese calendars) are Gregorian dates I concluded the same must be true for the Japanese eras. My bad.
>> 
>> According to a google translate of the Wikipedia page you kindly linked to, I see that:
>> 
>> 1. The dates are Julian years up to and including  Tenshō 天正
>> 2. Are Gregorian years after that
>> 
>> I can see that CLDR data follows the lunisolar month and day so thanks for that clarification.
>> 
>> My question is now whether CLDR dates for Japanese eras also change from Julian years to Gregorian years after Tenshō 天正?  A check of the data suggests “yes” - is that correct?
>> 
>> In trying to reconcile the data I also see:
>> 
>> Wikipedia:  Shōhō 正保 -> (Kanei December 16, 21, January 13, 1645, Julian year)
>> CLDR: <era type="199" start="1644-12-16"/>
>> 
>> Which suggest that either Wikipedia or CLDR have the wrong year for this era? The lunisolar months and days line up but the year is different.
>> 
>> Many thanks for your input and guidance!
>> 
>> Regards, —Kip
>> 
>> 
>> 
>> On 8 Sep 2021, at 7:09 pm, Wáng Yifán <747.neutron at gmail.com> wrote:
>> 
>>             <era type="186" start="1501-2-29"/>
>>             <era type="187" start="1504-2-30”/>
>> 
>> 
>> lol that's funny; only the year in Julius calendar and the rest are
>> lunisolar. Are they only invalid ISO dates in that file (I mean, there
>> should be other Feb 29s if dates are consistently recorded in
>> lunisolar)?
>> 
>> I cannot find any reference in TR35.
>> 
>> 
>> The Japanese WP has an exhaustive list:
>> https://ja.wikipedia.org/wiki/%E5%85%83%E5%8F%B7%E4%B8%80%E8%A6%A7_(%E6%97%A5%E6%9C%AC)
>> 
>> 
>> 2021年9月8日(水) 18:45 Kip Cole via CLDR-Users <cldr-users at corp.unicode.org>:
>> 
>> 
>> In supplementalData.xml, the era information for the Japanese calendar has two date entries which, in the Gregorian calendar, are not valid dates.
>> 
>>             <era type="186" start="1501-2-29"/>
>>             <era type="187" start="1504-2-30”/>
>> 
>> How should these dates be interpreted? I cannot find any reference in TR35. Are they intended to be interpreted as dates in the Japanese traditional lunisolar calendar?  If so, what epoch is assumed for the Japanese calendar?
>> 
>> Regards, —Kip
>> 
>> 
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