How the date is worked out
Tết is the first day of the Vietnamese lunisolar calendar. Its months begin at each new moon, and its year at the second new moon after the winter solstice, or the third in the rare years when a leap month comes between, so Tết falls between January 21 and February 20. The calendar is reckoned in Vietnam’s own time zone, which is why Tết usually shares its day with the Chinese New Year but now and then comes a day earlier.
The days around it
Families clean and decorate their homes in the last days of the old year, visit their ancestors’ graves and gather for a meal on New Year’s Eve. The first days of the year belong to visits: to the family first, then to friends and teachers, with red envelopes of lucky money for the children.