section_path: Variants/Chulasakarat
section_name: Chulasakarat
paragraph_text: Chulasakarat
  
  The Burmese calendar first came to be adopted in present-day northern Thailand in the mid-13th century, and in central Thailand by the second half of the 16th century. Although then mainland kingdoms of Lan Na, Lan Xang, Siam, and later Cambodia adopted the Burmese epoch starting at 638 CE, each region retained its own traditions and/or introduced its own modifications afterwards. For example, the Kengtung, Lan Na, Lan Xang, and Sukhothai calendars still retained the use of numbering the months even though the Burmese calendar stopped using the numbered months alongside the month names. The use of numbering system may have predated the introduction of the Burmese calendar in any case since each region had its own numbering system. The first numbered month in Kengtung, Lan Na, Lan Xang and Sukhothai calendars is Tazaungmon (Karttika), Thadingyut (Asvina), (Nadaw) Margasirsha, and (Nadaw) Margasirsha, respectively. This means reading ancient texts and inscriptions in Thailand requires constant vigilance, not just in making sure one is correctly operating for the correct region, but also for variations within regions itself when incursions cause a variation in practice. (Note: The Sukhothai and Lan Xang numbering systems and the now abandoned Burmese numbering system are the same.)
  
  Likewise, Cambodian and Thai systems have retained the practice of giving animal names to the years from a cycle of 12. The practice also existed in Burma in the Pagan period but later died out.
  
  Moreover, Chulasakarat uses three similar but not identical types of lunar years used by the Burmese calendar. Each calendar has the same regular year of 354 days and a leap year of 384 days. However, whereas the Burmese calendar adds the intercalary day only in a leap cycle according to its Metonic cycle, the Siamese calendar adds the intercalary day to a regular year. The Siamese calendar does add the extra day in the same place (Jyestha/Nayon), however.
  
  Lastly, the calculation methods also diverged in the mid-19th century when the Konbaung dynasty switched to the Thandeikta method, which is 0.56 second per year longer than the old system.