862. The Seudah Hamafsekes
123:3 The seudah hamafsekes is the last meal eaten before the fast. The proper course of action is to eat a normal meal before mincha, then to daven without reciting Tachanun since Tisha b'Av is considered a holiday (moed) as per Eicha (Lamentations) 1:15, "He called an assembly against me." (Editor's note: The word for assembly in this verse is also "moed.") Towards evening, we sit on the floor but we need not remove leather shoes. Three men should not sit together so as not to obligate them in forming a zimmun to bentch. (If three did eat together, they still don't form a zimmun - Mishnah Brurah 552:19.) We eat only bread and a cold hard-boiled egg; we dip a piece of bread in ashes and eat it. One must be careful to finish the meal while it is still day. (One may sit in a chair after the seudah hamafsekes until evening - Mishnah Brurah 552:18.)
123:4 If one has the practice to fast every Monday and Thursday year-round, and this would be the day before Tisha b'Av, he should seek to annul this commitment. If one has a yahrtzeit (Editor's note: for which some people fast) on the day before Tisha b'Av, the first time this happens, he should make a condition that he will fast only until after midday. He should daven at "mincha gedolah," which is a half hour after midday, and then eat a meal. He should eat the seudah hamafsekes after this, close to nightfall.