Ta'anit 12 Vowing to Fast as an Individual

The Gemara covers a number of conversations regarding those who vow to fast as individuals:

• Can a fast last only a few hours? (yes, with conditions)*
• When should one take on an individual fast?  That day?  The afternoon before? (the afternoon before is ideal, and this intention must be stated within the amidah prayer either aloud or internally)
• How do we mark the ending of a meal and the beginning of a fast?  The start of sleep and the beginning of a fast? (this is more tricky...)
• dozing: Rav Ashi defines dozing as when "one is asleep but not asleep, awake but not awake; that if they call him he will answer, but he cannot  give a reason.  And when we remind him, he remembers it".
• When is one allowed to 'borrow his fast and repay the fast' at a later date? (yes, with conditions)
• What is the difference between dream fasts and other individual fasts? (some say we should disregard dreams; others say that dream fasts should be undertaken the day following the dream, even if it falls on Shabbat, as this aligns with our observance of Shabbat)

A new Mishna compares this with individuals who join in a collective fast.  We learn how the community calls out to G-d for rain.  If the rain does not come, they move to the next stage of imploring G-d for help:

1. Three regular fasts
2. Three additional fasts: people can eat/drink during the day ('erev fast day'), and on the fast day they are prohibited from working, bathing, smearing themselves with oil, wearing shoes, marital relations; bathhouses are locked
3. Seven severe fasts (thirteen in total not including three fasts taken on by individuals): in addition to the above, they sound the alarm and they lock the stores, opening them only on Monday and Thursday for a short time in the evenings to allow people to prepare for breaking the fast and for Shabbat.
4. No more fasts, but more hardships: fewer business transactions, building, planing, betroths, marriages, greetings.  Individuals resume fasts on Mondays and Thursdays. 

When rain falls after Nisan, it is considered to be a curse (I Samuel 12:17).  

At the very end of our daf, Abaye describes fast days: From the morning until the middle of the day they look for flaws in city business.  Moral or other problems might be the cause of 'Divine punishment'.  The next quarter of the day is used to learn a portion from the Torah, a portion from the Prophets, as was advised in Nehemiah (9:3).

*Rav Yochanan was known to refuse dinner invitations from the Nasi by claiming that he had undertaken an individual fast -- and then he ate at home.  Lying to spare the feelings of others goes way, way back.