(If Mahadvadasi is in force, fasting is prohibited on the Ekadasi,
but the observance is done on the Dwadasi. Compound
Dwadasi-Mahadwadasi.)
There are eight special conditions when a dvadasi lunar tithi
becomes a Maha-dwadasi.
In such cases, fasting is done on the Maha-dwadasi and not the
ekadasi day.
NOTE: A Maha-dwadasi may be in effect for one location and not
another.
A regular dwadasi can also become a fast day for an ekadasi under
certain conditions.
1/. If Ekadasi begins after sunrise and ends before sunrise the
next day it is considered Lost, too short, thus not full, and
impure. Therefore the next day is called Unmillani Mahadwadasi.
2/. If Dwadasi begins after sunrise and ends before sunrise on the
next day (Trayodasi), it is also Lost, and is to be observed as
Tri-Sprsa-Mahadwadasi.
3/. If Dwadasi falls on the Sunrise two days in a row the first
Dwadasi becomes Vyanjuli Mahadwadasi.
4/. When the following Amavasya or Purnima falls on sunrise two
days in a row the preceeding Dwadasi becomes
Paksa-Vardhini-Mahadwadasi, Paksa based.
