[tz] China time zones 1949 - 1980: appeal to speakers of Mandarin
eggert at cs.ucla.edu
Tue Jul 1 06:09:26 UTC 2014
On 2014-04-22 Luther Ma wrote:
> computers and smart phones list Urumqi (or Kashgar) as having the same time as Beijing.
> I don't know why this would be a very big problem to fix. Then users can choose to set their computers or cell phones to Beijing time if they want, or to Xinjiang time if they want (instead of choosing some other locality like Dacca, which works until they go on daylight time.)
Good point, and thanks for looking into this and forwarding that info.
This combines with the problems that Alois Treindl has been reporting
for other Chinese time zones. I did a bit more research on my own into
timekeeping practice in Shanghai and came up with the attached proposed
patch, which I hope addresses the issues that you and Alois raised.
I've installed this into the experimental tz repository on github.
-------------- next part --------------
From 15b01c042afa770acd5068054c50e7c5c663cbd2 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert at cs.ucla.edu>
Date: Mon, 30 Jun 2014 22:51:00 -0700
Subject: [PATCH] Simplify China's time zones from five to two.
* NEWS, asia: Document this.
* asia (Asia/Harbin, Asia/Chongqing, Asia/Kashgar): Remove.
These are now links in 'backward'.
(Asia/Shanghai): Change pre-standard-time offset from 8:05:57 to
8:05:43. Change transition to standard time from 1928 to 1901.
(Asia/Urumqi): Remove 1980 transition to UTC+8.
* backward (Asia/Harbin, Asia/Chongqing, Asia/Kashgar): New links.
(Asia/Chungking): Avoid link-to-link.
* zone.tab (Asia/Harbin, Asia/Chongqing, Asia/Kashgar): Remove.
NEWS | 21 +++++++
asia | 203 +++++++++++++++++++++++++++++++++++++++++----------------------
backward | 5 +-
zone.tab | 7 +--
4 files changed, 161 insertions(+), 75 deletions(-)
diff --git a/NEWS b/NEWS
index 05a7063..df41f71 100644
@@ -12,8 +12,24 @@ Unreleased, experimental changes
This change does not affect UTC offsets, only time zone abbreviations.
(Thanks to Rich Tibbett and many others.)
+ The time zone abbreviation for Xinjiang Time (observed in Ürümqi)
+ has been changed from URUT to XJT. (Thanks to Luther Ma.)
Changes affecting past time stamps
+ China's five zones have been simplified to two, since the post-1970
+ differences in the other three seem to have been imaginary. The
+ zones Asia/Harbin, Asia/Chongqing, and Asia/Kashgar have been
+ removed; backwards-compatibility links still work, albeit with
+ different behaviors for time stamps before May 1980. Asia/Urumqi's
+ 1980 transition to UTC+8 has been removed, so that it is now at
+ UTC+6 and not UTC+8. (Thanks to Luther Ma and to Alois Treindl;
+ Treindl sent helpful translations of two papers by Guo Qingsheng.)
+ Asia/Shanghai's pre-standard-time UT offset has been changed from
+ 8:05:57 to 8:05:43, the location of Xujiahui Observatory. Its
+ transition to standard time has been changed from 1928 to 1901.
Finland's 1942 fall-back transition was October 4 at 01:00, not
October 3 at 00:00. (Thanks to Konstantin Hyppönen.)
@@ -54,6 +70,11 @@ Unreleased, experimental changes
are not already surrounded by white space. (Thanks to suggestions by
+ There is new commentary about Xujiahui Observatory, the five timezone
+ project in China from 1918 to 1949, timekeeping in Japanese-occupied
+ Shanghai, and Tibet Time in the 1950s. The sharp-eyed can spot the
+ warlord Jin Shuren in the data.
In zone.tab, Pacific/Easter no longer mentions Salas y Gómez, as it
diff --git a/asia b/asia
index 3f7d019..2ec40c9 100644
@@ -295,15 +295,16 @@ Zone Asia/Phnom_Penh 6:59:40 - LMT 1906 Jun 9
# CHINA 8 H AHEAD OF UTC ALL OF CHINA, INCL TAIWAN
# CHINA 9 H AHEAD OF UTC APR 17 - SEP 10
-# From Paul Eggert (2006-03-22):
-# Shanks & Pottenger write that China (except for Hong Kong and Macau)
-# has had a single time zone since 1980 May 1, observing summer DST
-# from 1986 through 1991; this contradicts Devine's
-# note about Time magazine, though apparently _something_ happened in 1986.
-# Go with Shanks & Pottenger for now. I made up names for the other
-# pre-1980 time zones.
+# From Paul Eggert (2008-02-11):
+# Jim Mann, "A clumsy embrace for another western custom: China on daylight
+# time - sort of", Los Angeles Times, 1986-05-05 ... [says] that China began
+# observing daylight saving time in 1986.
-# From Shanks & Pottenger:
+# From Paul Eggert (2014-06-30):
+# Shanks & Pottenger have China switching to a single time zone in 1980, but
+# this doesn't seem to be correct. They also write that China observed summer
+# DST from 1986 through 1991, which seems to match the above commentary, so
+# go with them for DST rules as follows:
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Shang 1940 only - Jun 3 0:00 1:00 D
Rule Shang 1940 1941 - Oct 1 0:00 0 S
@@ -328,53 +329,86 @@ Rule PRC 1987 1991 - Apr Sun>=10 0:00 1:00 D
# (could be true), for the moment I am assuming that those two
# counties are mistakes in the astro.com data.
-# From Paul Eggert (2008-02-11):
-# I just now checked Google News for western news sources that talk
-# about China's single time zone, and couldn't find anything before 1986
-# talking about China being in one time zone. (That article was: Jim
-# Mann, "A clumsy embrace for another western custom: China on daylight
-# time - sort of", Los Angeles Times, 1986-05-05. By the way, this
-# article confirms the tz database's data claiming that China began
-# observing daylight saving time in 1986.
-# From Thomas S. Mullaney (2008-02-11):
-# I think you're combining two subjects that need to treated
-# separately: daylight savings (which, you're correct, wasn't
-# implemented until the 1980s) and the unified time zone centered near
-# Beijing (which was implemented in 1949). Briefly, there was also a
-# "Lhasa Time" in Tibet and "Ürümqi Time" in Xinjiang. The first was
-# ceased, and the second eventually recognized (again, in the 1980s).
-# From Paul Eggert (2008-06-30):
-# There seems to be a good chance China switched to a single time zone in 1949
-# rather than in 1980 as Shanks & Pottenger have it, but we don't have a
-# reliable documentary source saying so yet, so for now we still go with
-# Shanks & Pottenger.
-# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-# Changbai Time ("Long-white Time", Long-white = Heilongjiang area)
+# From Paul Eggert (2014-06-30):
+# Alois Treindl kindly sent me translations of the following two sources:
+# Guo Qingsheng (National Time-Service Center, CAS, Xi'an 710600, China)
+# Beijing Time at the Beginning of the PRC
+# China Historical Materials of Science and Technology
+# (Zhongguo ke ji shi liao, 中国科技史料), Vol. 24, No. 1 (2003)
+# It gives evidence that at the beginning of the PRC, Beijing time was
+# officially apparent solar time! However, Guo also says that the
+# evidence is dubious, as the relevant institute of astronomy had not
+# been taken over by the PRC yet. It's plausible that apparent solar
+# time was announced but never implemented, and that people continued
+# to use UT+8. As the Shanghai radio station (and I presume the
+# observatory) was still under control of French missionaries, it
+# could well have ignored any such mandate.
+# Guo Qing-sheng (Shaanxi Astronomical Observatory, CAS, Xi'an 710600, China)
+# A Study on the Standard Time Changes for the Past 100 Years in China
+# [undated and unknown publication location]
+# It says several things:
+# * The Qing dynasty used local apparent solar time throughout China.
+# * The Republic of China instituted Beijing mean solar time effective
+# the official calendar book of 1914.
+# * The French Concession in Shanghai set up signal stations in
+# French docks in the 1890s, controled by Xujiahui (Zikawei)
+# Obervatory and set to local mean time.
+# * "From the end of the 19th century" it changed to UT+8.
+# * Chinese Customs (by then reduced to a tool of foreign powers)
+# eventually standardized on this time for all ports, and it
+# became used by railways as well.
+# * In 1918 the Central Observatory proposed dividing China into
+# five time zones (see below for details). This caught on
+# at first only in coastal areas observing UT+8.
+# * During WWII all of China was in theory was at UT+7. In practice
+# this was ignored in the west, and I presume was ignored in
+# Japanese-occupied territory.
+# * Japanese-occupied Manchuria was at UT+9, i.e., Japan time.
+# * The five-zone plan was resurrected after WWII and officially put into
+# place (with some modifications) in March 1948. It's not clear
+# how well it was observed in areas under Nationalist control.
+# * The People's Liberation Army used UT+8 during the civil war.
+# An AP article "Shanghai Internat'l Area Little Changed" in the
+# Lewiston (ME) Daily Sun (1939-05-29), p 17, said "Even the time is
+# different - the occupied districts going by Tokyo time, an hour
+# ahead of that prevailing in the rest of Shanghai." Guess that the
+# Xujiahui Observatory was under French control and stuck with UT+8.
+# In earlier versions of this file, China had many separate Zone entries, but
+# this was based on what was apparently incorrect data in Shanks & Pottenger.
+# This has now been simplified to the two entries Asia/Shanghai and
+# Asia/Urumqi, with the others being links for backward compatibility.
+# Proposed in 1918 and theoretically in effect until 1949 (although in practice
+# mainly observed in coastal areas), the five zones were:
+# Changbai Time ("Long-white Time", Long-white = Heilongjiang area) UT+8.5
+# Asia/Harbin (currently a link to Asia/Shanghai)
# Heilongjiang (except Mohe county), Jilin
-Zone Asia/Harbin 8:26:44 - LMT 1928 # or Haerbin
- 8:30 - CHAT 1932 Mar # Changbai Time
- 8:00 - CST 1940
- 9:00 - CHAT 1966 May
- 8:30 - CHAT 1980 May
- 8:00 PRC C%sT
-# Zhongyuan Time ("Central plain Time")
+# Zhongyuan Time ("Central plain Time") UT+8
# most of China
-# Milne gives 8:05:56.7; round to nearest.
-Zone Asia/Shanghai 8:05:57 - LMT 1928
- 8:00 Shang C%sT 1949
- 8:00 PRC C%sT
-# Long-shu Time (probably due to Long and Shu being two names of that area)
+# This currently represents most other zones as well,
+# as apparently these regions have been the same since 1970.
+# Milne gives 8:05:43.2 for Xujiahui Observatory time; round to nearest.
+# Guo says Shanghai switched to UT+8 "from the end of the 19th century".
+# Long-shu Time (probably due to Long and Shu being two names of that area) UT+7
+# Asia/Chongqing (currently a link to Asia/Shanghai)
# Guangxi, Guizhou, Hainan, Ningxia, Sichuan, Shaanxi, and Yunnan;
# most of Gansu; west Inner Mongolia; west Qinghai; and the Guangdong
# counties Deqing, Enping, Kaiping, Luoding, Taishan, Xinxing,
# Yangchun, Yangjiang, Yu'nan, and Yunfu.
-Zone Asia/Chongqing 7:06:20 - LMT 1928 # or Chungking
- 7:00 - LONT 1980 May # Long-shu Time
- 8:00 PRC C%sT
-# Xin-zang Time ("Xinjiang-Tibet Time")
+# Xin-zang Time ("Xinjiang-Tibet Time") UT+6
+# This currently represents Kunlun Time as well,
+# as apparently the two regions have been the same since 1970.
# The Gansu counties Aksay, Anxi, Dunhuang, Subei; west Qinghai;
# the Guangdong counties Xuwen, Haikang, Suixi, Lianjiang,
# Zhanjiang, Wuchuan, Huazhou, Gaozhou, Maoming, Dianbai, and Xinyi;
@@ -383,10 +417,9 @@ Zone Asia/Chongqing 7:06:20 - LMT 1928 # or Chungking
# Wusu, Qiemo, Xinyan, Wulanwusu, Jinghe, Yumin, Tacheng, Tuoli, Emin,
# Shihezi, Changji, Yanqi, Heshuo, Tuokexun, Tulufan, Shanshan, Hami,
# Fukang, Kuitun, Kumukuli, Miquan, Qitai, and Turfan.
-Zone Asia/Urumqi 5:50:20 - LMT 1928 # Ürümqi or Ürümchi
- 6:00 - URUT 1980 May # Ürümqi Time
- 8:00 PRC C%sT
-# Kunlun Time
+# Kunlun Time UT+5.5
+# Asia/Kashgar (currently a link to Asia/Urumqi)
# West Tibet, including Pulan, Aheqi, Shufu, Shule;
# West Xinjiang, including Aksu, Atushi, Yining, Hetian, Cele, Luopu, Nileke,
# Zhaosu, Tekesi, Gongliu, Chabuchaer, Huocheng, Bole, Pishan, Suiding,
@@ -417,19 +450,6 @@ Zone Asia/Urumqi 5:50:20 - LMT 1928 # Ürümqi or Ürümchi
# the province not having dual times but four times in use at the same
# time. Some areas remained on standard Xinjiang time or Beijing time and
# others moving their clocks ahead.)
-# ...an example of an official website using of Ürümqi time.
-# The first few lines of the Google translation of
-# (retrieved 2009-10-13)
-# > Ürümqi fire seven people are missing the alleged losses of at least
-# > 500 million yuan
-# > (Reporter Dong Liu) the day before 20:20 or so (Ürümqi Time 18:20),
-# > Ürümqi City Department of International Plaza Luther Qiantang River
-# > burst fire. As of yesterday, 18:30, Ürümqi City Fire officers and men
-# > have worked continuously for 22 hours...
# From Luther Ma (2009-11-19):
# With the risk of being redundant to previous answers these are the most common
@@ -452,10 +472,55 @@ Zone Asia/Urumqi 5:50:20 - LMT 1928 # Ürümqi or Ürümchi
# Autonomous Region under the PRC. (Before that Uyghurs, of course, would also
# not be using Beijing time, but some local time.)
-Zone Asia/Kashgar 5:03:56 - LMT 1928 # or Kashi or Kaxgar
- 5:30 - KAST 1940 # Kashgar Time
- 5:00 - KAST 1980 May
+# From David Cochrane (2014-03-26):
+# Just a confirmation that Ürümqi time was implemented in Ürümqi on 1 Feb 1986:
+# From Luther Ma (2014-04-22):
+# I have interviewed numerous people of various nationalities and from
+# different localities in Xinjiang and can confirm the information in Guo's
+# report regarding Xinjiang, as well as the Time article reference by David
+# Cochrane. Whether officially recognized or not (and both are officially
+# recognized), two separate times have been in use in Xinjiang since at least
+# the Cultural Revolution: Xinjiang Time (XJT), aka Urumqi Time or local time;
+# and Beijing Time. There is no confusion in Xinjiang as to which name refers
+# to which time. Both are widely used in the province, although in some
+# population groups might be use one to the exclusion of the other. The only
+# problem is that computers and smart phones list Urumqi (or Kashgar) as
+# having the same time as Beijing.
+# From Paul Eggert (2014-06-30):
+# In the early days of the PRC, Tibet was given its own time zone (UT+6) but
+# this was withdrawn in 1959 and never reinstated; see Tubten Khétsun,
+# Memories of life in Lhasa under Chinese Rule, Columbia U Press, ISBN
+# 978-0231142861 (2008), translator's introduction by Matthew Akester, p x.
+# As this is before our 1970 cutoff, Tibet doesn't need a separate zone.
+# Xinjiang Time is well-documented as being officially recognized. E.g., see
+# "The Working-Calendar for The Xinjiang Uygur Autonomous Region Government"
+# <http://www.sinkiang.gov.cn/service/ourworking/> (2014-04-22).
+# Unfortunately, we have no good records of time in Xinjiang before 1986.
+# During the 20th century parts of Xinjiang were ruled by the Qing dyansty,
+# the Republic of China, various warlords, the First and Second East Turkestan
+# Republics, the Soviet Union, the Kuomintang, and the People's Republic of
+# China, and tracking down all these organizations' timekeeping rules would be
+# quite a trick. Approximate this lost history by a transition from LMT to
+# XJT at the start of 1928, the year of accession of the warlord Jin Shuren,
+# which happens to be the date given by Shanks & Pottenger (no doubt as a
+# guess) as the transition from LMT. Ignore the usage of UT+8 before
+# 1986-02-01 under the theory that the transition date to UT+8 is unknown and
+# that the sort of users who prefer Asia/Urumqi now typically ignored the
+# UT+8 mandate back then.
+# Zone NAME GMTOFF RULES FORMAT [UNTIL]
+# Beijing time, used throughout China; represented by Shanghai.
+Zone Asia/Shanghai 8:05:43 - LMT 1901
+ 8:00 Shang C%sT 1949
8:00 PRC C%sT
+# Xinjiang time, used by many in western China; represented by Ürümqi / Ürümchi
+# / Wulumuqi. (Please use Asia/Shanghai if you prefer Beijing time.)
+Zone Asia/Urumqi 5:50:20 - LMT 1928
+ 6:00 - XJT
# Hong Kong (Xianggang)
diff --git a/backward b/backward
index f3cf8cc..50952e8 100644
@@ -26,8 +26,11 @@ Link America/Port_of_Spain America/Virgin
Link Pacific/Auckland Antarctica/South_Pole
Link Asia/Ashgabat Asia/Ashkhabad
Link Asia/Kolkata Asia/Calcutta
-Link Asia/Chongqing Asia/Chungking
+Link Asia/Shanghai Asia/Chongqing
+Link Asia/Shanghai Asia/Chungking
Link Asia/Dhaka Asia/Dacca
+Link Asia/Shanghai Asia/Harbin
+Link Asia/Urumqi Asia/Kashgar
Link Asia/Kathmandu Asia/Katmandu
Link Asia/Macau Asia/Macao
Link Asia/Ho_Chi_Minh Asia/Saigon
diff --git a/zone.tab b/zone.tab
index aa4ef18..08d9ba6 100644
@@ -155,11 +155,8 @@ CK -2114-15946 Pacific/Rarotonga
CL -3327-07040 America/Santiago most locations
CL -2709-10926 Pacific/Easter Easter Island
CM +0403+00942 Africa/Douala
-CN +3114+12128 Asia/Shanghai east China - Beijing, Guangdong, Shanghai, etc.
-CN +4545+12641 Asia/Harbin Heilongjiang (except Mohe), Jilin
-CN +2934+10635 Asia/Chongqing central China - Sichuan, Yunnan, Guangxi, Shaanxi, Guizhou, etc.
-CN +4348+08735 Asia/Urumqi most of Tibet & Xinjiang
-CN +3929+07559 Asia/Kashgar west Tibet & Xinjiang
+CN +3114+12128 Asia/Shanghai Beijing Time
+CN +4348+08735 Asia/Urumqi Xinjiang Time
CO +0436-07405 America/Bogota
CR +0956-08405 America/Costa_Rica
CU +2308-08222 America/Havana
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