1. Laws of the Eve of Tisha B'av containing 12 paragraphs. On the Eve of Tisha B'av in the Parting Meal-- that is eaten after Halachic Noon-- a person should not eat meat and should not drink wine, and he should not eat two cooked dishes. Note (Rema): Even other drinks, one should reduce the amount he normally drinks [Tur and Bais Yosef in the name of Tosafos and Rokeach] and similarly, he should not eat after the Meal radishes and salted food that he is used to on other occasions in order to accustom himself in asceticism. [Mordechai]
2. Even salted meat more than 2 days and one night old; or the meat of fowl, fish, or newly pressed wine that is less than 3 days old, the custom is to forbid.
3. Even one item cooked in two pots is called two dishes and so it's advisable to be strict and careful to avoid two items in one pot-- unless this is the normal manner it is cooked during the whole year; for example chickpeas types of vegetables and in our language ciceri that they put onions and eggs on them. A cooked dish that is made from something that can be eaten raw is called a cooked dish in this matter. Note (Rema): And there is no distinction between a roasted food and a cooked one in this matter [Mordechai Laws of Tisha B'av]
4. It is permitted to eat fruits when they are raw, even multiple types.
5. We customarily eat lentils with cooked eggs in them that are the food of mourners. Note (Rema): There are those that are accustomed to eat hardboiled eggs that are also a food of mourners [Haagos Maimoni Chapter 5]
6. One who is able should only eat burnt bread in salt and a flask of water in the Parting Meal. Note (Rema): There are those that are strict after eating the bread to dip into ash and to eat on the word(s) "And he has broken in gravel..." (Lamentations 3:15)
7. There is a custom to sit on the ground during the Parting Meal Parentheses: and it is not necessary to take off his shoes [Hagahot Maimoni and Rambam Chapter 7 and Beit Yosef]
8. One should be cautious not to sit in a group of three at the Parting Meal in order that they will not become obligated in a Zimun; rather, each one sits alone and blesses (i.e. Birkat Hamazon) alone.
9. And all this applies at a Parting Meal where one does not intend to eat more in a regular meal after it and when eaten after Halachic Noon. But if it is before Halachic Noon, or after Halachic Noon but his intention is to eat an established meal after, it is not necessary to be careful in these matters. Note (Rema): And the custom is in all the provinces of Ashkenaz to eat an established meal before Mincha, and to pray Mincha after, and then eat the Parting Meal. [Maharil] We are accustomed to add a little more (food) to this first meal in order that the fast not hurt them, since we stop eating while it is still day, just like on Yom Kippur. And there is a slight proof for this from the Midrash Eichah Rabbati. However, one who is able to afflict himself and knows for himself that the fast won't be a harm to him and is strict on himself is called a Kadosh (Holy Person), so it seems to me.
10. If Tisha B'av falls on Sunday or Shabbat and is pushed off until after Shabbat, one eats meat and drinks wine in the Parting Meal, and their table can be elevated even like a meal on King Solomon's table at the time of his Kingship Parentheses (Rema): However it is necessary to stop eating while still day [S'mak]
11. One who accepted upon himself to fast every Monday and Thursday all the days of the year, and it happens that the eve of Tisha B'av is on Monday: He should ask upon his vow (i.e. to nullify it) or borrow his fast and pay it back (i.e. fast another day instead). Note (Rema): The Gaonim write that he should fast until after the Mincha Prayers and eat the Parting Meal before the setting of the sun [Hagahot Ashiri and Mordechai and Terumat Hadeshen Chapter 75], and so we are accustomed. And the same rule applies to one who fasts a "Dream Fast" [Maharil].
12. We do not say Tachanun on the eve of Tisha Bav at Mincha because it is called a "Moed" (Festival). Parentheses (Rema): If it is Shabbat, we do not say Tzidkat'kha [Maharil and Minhagim].