Here is a simple, tradition‑faithful overview of Jain fasts (tapas) and food‑restraint practices.

A. The six external austerities (bahya tapa) These are the classic Jain “fasting-related” practices:

• Anashana: complete fasting from food (and sometimes water).
• Unodari: eating less than one’s hunger.
• Vritti‑parisankhyana: limiting the kinds, number, or sources of foods accepted.
• Rasaparityaga: giving up tasty/rich items (like sweets, fried foods, spices).
• Vivikta‑shayyasan: staying in seclusion and simple lodging to reduce wants.
• Kayaklesha: bearing bodily hardship for spiritual purification (within non‑violence).

B. Daily/occasional food‑restraint observances (widely followed by householders)

• Navkarsi: first intake only after about 48 minutes post‑sunrise.
• Porasi, Sadh‑porasi, Porsi, Avaddha: taking the first meal progressively later in the day (about 3, 4.5, 6, 9 hours after sunrise).
• Ekasana: only one meal in one sitting.
• Beasana: only two sittings/meals in a day.
• Ayambil: one very plain meal in a day, without taste enhancers.

• Shvetambar tradition: typically one meal of bland, simple items (no milk/curd/ghee/oil/sweets, very minimal spices; often only boiled grains/pulses). • Digambar tradition: similarly plain and austerity‑focused; exact permitted items may vary by local acharya’s guidance.

• Upavasa (full fast for ~24 hours):

• Shvetambar: no food; only boiled water during daylight hours (many observe “tivihar upvas” with water, or “chauvihar upvas” without water after sunset). • Digambar: commonly a nirjala upavasa (no food and no water) unless instructed otherwise.

• Chauvihar: after sunset, no food (and often no water) until after sunrise the next day.
• Tivihar: water permitted after sunset is restricted or avoided depending on local guidance.
• Paushadha/Pausadha: living like a monk/nun for a day (or more) with strict conduct; often combined with fasting or very restricted diet.

C. Extended and named fasts

• Attham: three consecutive days of total fasting (ends on the 8th lunar day).
• Aththai (Atthai): eight consecutive days of total fasting.
• Masakshamana: continuous fasting for about a month (traditionally only boiled water in daylight for Shvetambar; Digambar often nirjala unless guided otherwise).
• Varsitap: alternate‑day fasting for approximately one year (from one Akshaya Tritiya to the next), ending with parana on Akshaya Tritiya.
• Pakkhi/Pratipada‑Ashtami/Chaturdashi fasts: periodic fasts on set lunar days.
• Oli / Navpad Oli (Shvetambar): nine days of Ayambil, twice a year (Chaitra and Ashwin), devoted to the nine spiritual excellences (Navapada).
• Dashalakshana/Paryushan observances: many undertake Ekasana, Ayambil, Upavasa, Attham, etc., according to capacity and guidance.
• Upadhan tapa (regional/tradition‑specific): a structured sequence (often ~47 days) combining Ayambil, Ekasana, and Upavasa as taught by one’s acharya.

Notes on tradition differences

• Water during fasts: Shvetambar laity commonly take only boiled water during daylight on fasting days; Digambar practice often emphasizes nirjala (no water), unless a guru prescribes otherwise.
• Ayambil rules: exact permitted grains/pulses, spices, and cooking methods can differ slightly between Digambar and Shvetambar communities; follow your sangh/acharya.
• All fasts should be undertaken with right faith, non‑