Below is more information that might help to determine the border of the Uzbekistan zones. Since there have been changes to the subdivisions in the region that may contain the border between the zones, there may be a requirement to establish a new zone, e.g. if each subdivision only observed one offset at a time. The issue of insufficient information to determine what geographic areas are covered by the zones for Uzbekistan had been raised already 2008-09-08 by Eric Muller: http://mm.icann.org/pipermail/tz/2008-September/015069.html "What is the boundary between Asia/Samarkand and Asia/Tashkent?" As of today at http://efele.net/maps/tz/world/ it says "Uzbekistan This country is covered by two tz timezones, Tashkent and Samarkand. There is not enough information in the tz data to figure out how Uzbekistan is divided between them. We use a separation along first-level administrative divisons that matches WTE." tzdata2012c/asia says ----------- # Uzbekistan # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Asia/Samarkand 4:27:12 - LMT 1924 May 2 4:00 - SAMT 1930 Jun 21 # Samarkand Time 5:00 - SAMT 1981 Apr 1 5:00 1:00 SAMST 1981 Oct 1 6:00 - TAST 1982 Apr 1 # Tashkent Time 5:00 RussiaAsia SAM%sT 1991 Sep 1 # independence [two lines follow which are the same for both zones] Zone Asia/Tashkent 4:37:12 - LMT 1924 May 2 5:00 - TAST 1930 Jun 21 # Tashkent Time 6:00 RussiaAsia TAS%sT 1991 Mar 31 2:00 5:00 RussiaAsia TAS%sT 1991 Sep 1 # independence [two lines follow which are the same for both zones] ------------- According to the Theory file a zone must only include territory where the clock's timestamps agreed after 1970-01-01 00:00:00 UTC. According to "asia"-file between 1930-06-21 and 1981-04-01 Samarkand had UTC+4 while Tashkent had UTC+5. So there is at least a difference in timestamp from 1970 until 1981 and the requirements for having at least two zones are met. Q1: What were the 1970-01-01 subdivisions located between Samarkand in the west and Tashkent in the east? http://www.departments.bucknell.edu/russian/const/36cons01.html gives 1936 CONSTITUTION OF THE USSR ... ARTICLE 26. The Uzbek Soviet Socialist Republic consists of the Bukhara, Samarkand, Tashkent, Ferghana, and Khorezm Regions, and the Kara-Kalpak Autonomous Soviet Socialist Republic. There is a map that shows Bukhara, Samarkand, Tashkent, Ferghana, and Khorezm oblasts and the ASSR. http://commons.wikimedia.org/wiki/File:Map_of_Uzbek_SSR_01.12.1938.jpg Samarkand Oblast in its east is only bordered by Tashkent Oblast and Tashkent Oblast in its west is only bordered by Samarkand Oblast. Syr Darya Oblast may have been formed 1963-02-16 according to http://encyclopedia2.thefreedictionary.com/Syr+Darya+Oblast http://statoids.com/uuz.html claims "1963-02-16: Syr-Darya oblast split from Samarkand." So 1970-01-01 there have been from west to east -Samarkand Oblast -Syr-Darya Oblast -Tashkent Oblast The territories of these entities might contain the border between Asia/Tashkent and Asia/Samarkand. Q2: What changes to subdivisions did occur after 1970-01-01? http://encyclopedia2.thefreedictionary.com/Syr+Darya+Oblast says "In 1973 a large part of the oblast’s territory was transferred to the newly formed Dzhizak Oblast.", while http://statoids.com/uuz.html claims "1973-12-29: Dzhizak oblast split from Samarkand." According to ru WP in 1982 and according to http://statoids.com/uuz.html in "~1981" Navoiy Oblast has been created. According to all three sources in 1973 between Samarkand Oblast in the west and Tashkent Oblast in the east there seem to have been two new oblasts compared with 1936, Dzhizak in the west and Syr-Darya in the east. Corresponding viloyats / provinces today from west to east are - Samarqand Viloyat - Jizzakh Viloyat - Sirdaryo Viloyat - Tashkent Viloyat statoids only records one change in that area after these four have been created, namely "~1996: Tashkent City split from Tashkent region". -- Tobias Conradi Rheinsberger Str. 18 10115 Berlin Germany http://tobiasconradi.com/