Answer

No, doing Chauvihar, Tivihar, or Duvihar at night does not automatically mean you must do Navkārshi the next morning.

Explanation

In Jain practice:

• Chauvihar means giving up all food and water after sunset until the next day.
• Tivihar usually means giving up food, but allowing boiled water according to the accepted time rules.
• Duvihar means a lighter form of restriction, depending on family or sect practice.
• Navkārshi means eating or drinking only after a certain time in the morning, traditionally after sunrise and after completing the proper time duration.

These are related practices, but they are not the same vow.

So, if you simply did Chauvihar, Tivihar, or Duvihar for the night, you may break it the next morning according to your family, guru, or sampradāy practice. Navkārshi is an additional discipline if you have specifically taken that intention or vow.

Spiritual Understanding

The main purpose of these practices is restraint, awareness, and reduction of attachment to food and taste. Navkārshi adds further discipline by delaying food and drink in the morning.

If you have taken a clear pachchakkhān for Navkārshi, then you should observe it properly. If you have not taken that vow, it is not automatically required just because you did Chauvihar, Tivihar, or Duvihar.

Takeaway

Chauvihar/Tivihar/Duvihar and Navkārshi are separate practices. If you specifically vowed Navkārshi, then follow it. Otherwise, doing night restraint alone does not necessarily require Navkārshi the next morning.