[tz] [PATCH] Fix Asia/Shanghai 1940/9 DST transitions
Phake Nick
c933103 at gmail.com
Tue Oct 2 20:39:11 UTC 2018
Note: The DST in year 1949 listed in the essay is only theoretical
according to the essay. Because the ROC regime was progressively being
wiped out from mainland China at the year and Communist force have taken
over Shanghai in May that year (May 28 per wiki). It doesn't say what
actually happened that year other than citing a Shanghai newspaper from
mid-April that year which indicated there were still plan to implement DST
that year.
Also relevant: Around the time People's Republic of China establish that
year, which mean around October 1, 1949, government of Beijing announced
their switch to use Beijing time instead of the Chinese Plate Time that was
used in Eastern China before, and the switch was subsequently followed by
central government organizations in Beijing as well as various local
governments independently without any formal order. It was thought as only
a change in name in the standard time as both Beijing and Nanjing/Shanghai
are both GMT+8, however Guo Qing-sheng wrote an essay in 2003 saying that
at the time the switch probably mean a switch to local solar time of
Beijing as there were document from formerly UTC+7-area railway department
that change their schedule by 56 minutes when they shift the clock to
Beijing time, which would match the true solar time of Beijing. (Mean solar
time of Beijing is GMT+7:46, and then at that time of the year the true
solar time of Beijing would be roughly +10 minutes from its mean solar
time, and then he also quoted an astronomers who attended astronomical
society AGM at Nanjing in 1949 saying at the time there were many
discussion about using "Peking Mean Time/Peking Time" as Beijing Time
(Peking was the romanization for Beijing at the time; the astronomer wrote
it this way in his personal letter to the essay author) and they have sent
people to Beijing to discuss about the issue at the time. However there are
not much other information about it other than they most likely switched
back to GMT+8 by 1954.
2018-10-2 17:03, Paul Eggert <eggert at cs.ucla.edu> wrote:
> * NEWS: Mention this.
> * asia (Shang): Switch to data from 2014 Li Yu paper.
> ---
> NEWS | 3 +++
> asia | 34 +++++++++++++++++++++++++++-------
> 2 files changed, 30 insertions(+), 7 deletions(-)
>
> diff --git a/NEWS b/NEWS
> index a24d4b3..e217a50 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -42,6 +42,9 @@ Unreleased, experimental changes
> zic turns this into 01:00 on the day after September's second
> Saturday, which is the best that POSIX or C platforms can do.
>
> + Incorporate 1940-1949 Asia/Shanghai DST transitions from a 2014
> + paper by Li Yu, replacing more-questionable data from Shanks.
> +
> Changes to time zone abbreviations
>
> Use "PST" and "PDT" for Philippine time. (Thanks to Paul Goyette.)
> diff --git a/asia b/asia
> index 365593a..a7b5c75 100644
> --- a/asia
> +++ b/asia
> @@ -286,6 +286,29 @@ Zone Asia/Yangon 6:24:47 - LMT
> 1880 # or Rangoon
>
> # China
>
> +# From Paul Eggert (2018-10-02):
> +# The following comes from Table 1 of:
> +# Li Yu. Research on the daylight saving movement in 1940s Shanghai.
> +# Nanjing Journal of Social Sciences. 2014;(2):144-50.
> +#
> http://oversea.cnki.net/kns55/detail.aspx?dbname=CJFD2014&filename=NJSH201402020
> +# The table lists dates only; I am guessing 00:00 and 24:00 transition
> times.
> +# Also, the table lists the planned end of DST in 1949, but the
> corresponding
> +# zone line cuts this off on May 27, when the Communists took power.
> +#
> +# Rule NAME FROM TO TYPE IN ON AT SAVE
> LETTER/S
> +Rule Shang 1940 only - Jun 1 0:00 1:00 D
> +Rule Shang 1940 only - Oct 12 24:00 0 S
> +Rule Shang 1941 only - Mar 15 0:00 1:00 D
> +Rule Shang 1941 only - Nov 1 24:00 0 S
> +Rule Shang 1942 only - Jan 31 0:00 1:00 D
> +Rule Shang 1945 only - Sep 1 24:00 0 S
> +Rule Shang 1946 only - May 15 0:00 1:00 D
> +Rule Shang 1946 only - Sep 30 24:00 0 S
> +Rule Shang 1947 only - Apr 15 0:00 1:00 D
> +Rule Shang 1947 only - Oct 31 24:00 0 S
> +Rule Shang 1948 1949 - May 1 0:00 1:00 D
> +Rule Shang 1948 1949 - Sep 30 24:00 0 S
> +
> # From Guy Harris:
> # People's Republic of China. Yes, they really have only one time zone.
>
> @@ -336,12 +359,9 @@ Zone Asia/Yangon 6:24:47 - LMT
> 1880 # or Rangoon
> # http://data.people.com.cn/pic/101p/1988/04/1988041201.jpg
>
> # 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
> -Rule Shang 1941 only - Mar 16 0:00 1:00 D
> -Rule PRC 1986 only - May 4 2:00 1:00 D
> -Rule PRC 1986 1991 - Sep Sun>=11 2:00 0 S
> -Rule PRC 1987 1991 - Apr Sun>=11 2:00 1:00 D
> +Rule PRC 1986 only - May 4 2:00 1:00 D
> +Rule PRC 1986 1991 - Sep Sun>=11 2:00 0 S
> +Rule PRC 1987 1991 - Apr Sun>=11 2:00 1:00 D
>
> # From Anthony Fok (2001-12-20):
> # BTW, I did some research on-line and found some info regarding these
> five
> @@ -543,7 +563,7 @@ Rule PRC 1987 1991 - Apr
> Sun>=11 2:00 1:00 D
> # 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 Shang C%sT 1949 May 27
> 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.)
> --
> 2.17
>
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