Sri Nrsimha Jayanti is Shukla Chaturdashi of the lunar month Vaisakha. Ahnika Grantham asks that no Trayodashi be mixed into its morning. Nava settles a Chaturdashi that spans two days by a 12-nazhigai rule taken from the Ahobila Mutt's almanac, and the two tests can pick different days. For the date itself, the printed almanac of your tradition decides. A book's rule explains a date; it does not overrule the almanac.
☕ The rule in plain words
Ahnika Grantham gives the festival as Vaisakha Shukla Chaturdashi, without Trayodashi mixed into the morning for 3 muhurtham (6 nazhigai) (Ahnika Grantham, Vol. 1 (Sri Ahobila Mutt), p. 333). It notes that some temples keep the day on a different basis.
The Mutt's almanac uses a 12-nazhigai rule for a thirunakshatram, and its printed Upakarma days follow the same rule for a tithi (Sri Nrisimha Priya, the Ahobila Mutt's almanac). Nava uses it here too; no page of the almanac states it for this festival. A tithi belongs to the last day whose sunrise it stands on, if it runs at least 12 nazhigai (4 hours 48 minutes) past that sunrise. If it runs less, it belongs to the day before. A Chaturdashi that stands at no sunrise belongs to the day it begins.
So a Chaturdashi that ends soon after a sunrise does not take that day: the day it began keeps the festival. That earlier day can have Trayodashi in its morning for more than 6 nazhigai, which the book's test refuses.
At a glance
- Month: lunar Vaisakha, the regular (nija) month.
- Tithi: Shukla Chaturdashi.
- The book: no Trayodashi in the morning for 6 nazhigai.
- Nava, two days? The later day keeps it only if Chaturdashi runs 12 nazhigai or more past its sunrise.
- Chaturdashi at no sunrise: the day it begins.
- What Nava does: Sri Narasimha Jayanti is kept by this 12-nazhigai rule, on Shukla Chaturdashi of nija Vaisakha. The book's 6-nazhigai Trayodashi test is not run, so in some years the two give different days.
Frequently asked questions
Why is Nrsimha Jayanti sometimes on the day Trayodashi holds sunrise?
Because the Chaturdashi began that day and ended less than 12 nazhigai after the next sunrise. Under the 12-nazhigai rule the earlier day owns it.
Is the 12-nazhigai rule special to this festival?
No. The Mutt uses it for a thirunakshatram, and its Yajur Upakarma days follow it. Nava applies it to the festivals whose rule names it.
Do all temples keep the same day?
Not always. Ahnika Grantham itself notes that some temples keep it on a different basis. Follow your temple’s or tradition’s almanac.
Deep dive: the 12-nazhigai rule on two sample years
Sunrise 06:00 on both days. One nazhigai is 24 minutes.
🧮 Ends early, ends late
- Chaturdashi runs from Monday 07:30 to Tuesday 08:30. On Tuesday it runs 2 hours 30 minutes past sunrise, under 12 nazhigai, so Monday keeps the festival.
- Chaturdashi runs from Monday 11:00 to Tuesday 11:30. On Tuesday it runs 5 hours 30 minutes past sunrise, over 12 nazhigai, so Tuesday has it.
🔗 Read first
This page builds on vyapti, which tithi owns the day, which explains the idea of a tithi owning a day.