"Zhe Su" <james.su@gmail.com> writes:

Nowadays, China uses only one unified timezone, which is known as "China Beijing time", so using Asia/Beijing instead of Asia/Shanghai is more reasonable.

We used to use Zone names like that, but this approach scaled poorly to the practical problem of recording all the world's time zone and daylight saving time rules since 1970. So in 1993 we switched to the current method of identifying every region of like-minded clocks by its most populous location (e.g., "America/Los_Angeles"). This issue is discussed in the 'Theory' file, which mentions Shanghai and Beijing as an example. It should also help to explain why China has five entries, not one. The Zone name is an internal identifier, and is not intended to correspond to the name that people commonly use for the time zone. For example, the Zone name Europe/London corresponds to what is commonly called "Greenwich time" during winter, and there is no Zone named "Europe/Greenwich". Ordinary users are expected to employ a front end that maps their favorite names to the internal identifier. In China I would expect the favorite name to be the Chinese equivalent of "China Standard Time". If you'd like to do that sort of thing, I suggest <http://unicode.org/cldr/data/diff/by_type/dates_timeZoneNames.html>, which contains several strings that a front end could use for Asia/Shanghai, including "China Standard Time" in English, "Chinese standaardtijd" in Dutch, and so forth. There are two different Chinese translations (I don't know why). This is all part of the Common Locale Data Repository (CLDR) Project <http://unicode.org/cldr/>. If you find an error in the Chinese strings, you can report them as described in <http://unicode.org/cldr/filing_bug_reports.html>. You might be amused to hear that the Shanghai Daily stopped putting the phrase "Beijing Time" atop their stories last month, because others incorrectly credited the stories to the "Beijing Times" newspaper. See <http://www.shanghaidaily.com/editor/2006/03/02/goodbye-beijing-time/>.