[tz] Fwd: Historical timezone data for Bonin Islands (Ogasawara)

Phake Nick c933103 at gmail.com
Tue Feb 12 08:22:26 UTC 2019

Hello all,
I have recently received some new information about timezone history of
Bonin Islands, Japan as detailed in the attached message.
Because their last time change to return to Japanese time when they return
to Japanese rule was right before 1970, it mean per the current tz database
rule, the information doesn't warrant creation of a new timezone for Bonin
Islands itself and is thus as an anecdotal note for interest purpose only.
However, in the attached link, it described some special timekeeping
phenomenon regarding Marcus island, another remote island currently owned
by Japanese in the same administrative unit as Bonin Islands.
Many reports claim that the American coastal guard on the American quarter
of the island use its own coastal guard time, and most sources describe the
time as UTC+11, being two hours faster than JST used by some Japanese
personnel on the island. Some sites describe it as same as Wake Island/Guam
time although it would be incorrect to be same as Guam.
And then in a few Japanese governmental report from 1980s (from National
Institute of Information and Communications Technology) regarding the
construction of VLBI facility on the Marcus Island, it claimed that
there're three time standard being used on the island at the time which
include not just JST (UTC+9) or [US]CG time (UTC+11) but also a JMSDF time
(UTC+10) (Japan Maritime Self-Defense Force). Unfortunately there are no
other sources that mentioned such time and there are also no information on
things like how the tine was used.

---------- Forwarded message ---------
From: Wakaba
Date: 2019-1-28 Mon 13:48
Subject: Re: Question related to the page 昭和のサマータイム on suikawiki
To: Phake Nick

>> Hello, I see that there're a lot of information about DST at the time in
Japan on Suikawiki, but a special area that's not mentioned in the page os
Ogasawara 小笠原諸島 (Bonin Islands) which seems to have its own different
history of governance. Do you know where can information related to
timezone of the islands can be found?

> Unfortunately we have no reliable source on time in US-controlled
Ogasawara Islands at the moment.

It turns out that National Diet Library of Japan has several reports
by Japanese Government officers that describe the time used in islands
when they visited there. According to them (and other sources such as
newspapers), standard time UTC + 10 (JST + 1) and DST UTC + 11 (JST +
2) was used until its return to Japan at 1968-06-26 00:00 JST.

The exact periods of DST are still unknown. I guessed Guam, Mariana,
and Bonin and Marcus districts might have synchronized their DST
periods, but reports imply they had their own decisions, i.e. there
were three or more different time zones.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mm.icann.org/pipermail/tz/attachments/20190212/ce29e65a/attachment.html>

More information about the tz mailing list