From 15b01c042afa770acd5068054c50e7c5c663cbd2 Mon Sep 17 00:00:00 2001 From: Paul Eggert 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 --- a/NEWS +++ b/NEWS @@ -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 Steffen Nurpmeso.) + 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 is uninhabited. diff --git a/asia b/asia index 3f7d019..2ec40c9 100644 --- a/asia +++ b/asia @@ -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: +# +# (1) +# 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. +# +# (2) +# 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 +# Asia/Shanghai # 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 +# Asia/Urumqi +# 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 -# http://www.fjysgl.gov.cn/show.aspx?id=2379&cid=39 -# (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: +# http://content.time.com/time/magazine/article/0,9171,960684,00.html + +# 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" +# (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 --- a/backward +++ b/backward @@ -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 --- a/zone.tab +++ b/zone.tab @@ -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 -- 1.9.1