On 2019-08-08 13:32, Alois Treindl wrote:

In view of this, I would tend to eliminate the line
                        8:00    -       +08     1953 Nov  9

   Hm. The observations you quote are consistent with the
   current description in tzdb which uses UT + 08 h
   instead of UT + 07 h from 1947-04-01 until various dates
   (between 1953 to 1955) in former French Indochina. So
   all of Indochina used the same civil time in 1951.

   And then there is the book referenced in tzdb for Vietnam
   with positive evidence.

   Michael Deckers.

However, on 7 January 1946, Sihanouk and Tioulong managed to obtain a status of “internal autonomy” from the government of Charles de Gaulle. Although many fields remained under the administration of the French (customs, taxes, justice, defence, foreign affairs, etc.), the Cambodian administration was responsible for religious matters and traditional celebrations, which included our calendar and time. The time zone was GMT + 7 and no DST was applied.