From sunrise, if a given nakshatram exists for 12 nazhigai-s, those born under that nakshatram must celebrate their birthday on that day. If it does not exist for 12-nazhigai-s, the birthday is celebrated the previous day. If a nakshatram occurs twice during a month, on the second occurrence, if there is no association with Sankramanam, it must be celebrated then; if there is a taint on the second occurrence, the birthday is celebrated during the first occurrence of the nakshatram.

