Even though the twelve-animal cycle giving the name of a different animal to a year is quite common all over Thailand, it is generally not known which day the year gets a new name, as this depends on the traditional calendar which is largely forgotten. As a result, there are quite a few conflicting interpretations concerning the day when a new year starts in the cycle and the tradition is often wrongly adapted to modern calendar practices, with a strong interference of foreign influences. To illustrate the question, the article reviews the various interpretations concerning the day when the year 2000 became a year of the big serpent, showing that no less than five options are found for this single year.Hennequin Laurent. Quand l'an 2000 est...