Navkarsi is a traditional Jain time for taking the first food or water of the day.

In simple words:

• What is Navkarsi?

The first meal (or first drinking of water) taken after sunrise, only after about 48 minutes have passed.

• How is the time decided?

- Find today’s sunrise time in your city. - Add about 48 minutes. - That moment is called Navkarsi. Example: - Sunrise at 6:00 am → Navkarsi around 6:48 am.

• Rule:

From previous day’s sunset till Navkarsi time next morning – no food and no water (if you are keeping proper chauvihar + navkarsi).

• Why is it done?

- To start the day with discipline and saiyam. - Time before Navkarsi is used for snan, pooja, samayik, pratikraman, Navkar mantra, etc. - Eating a little later, in proper daylight, helps reduce himsā of tiny living beings and supports health and mindfulness.

• Digambar / Shwetambar:

Both traditions follow the same basic idea: Navkarsi ≈ 48 minutes after sunrise. Small differences may be there by local sangh or panchang.

You can read more in detail here