Erev Tisha B’Av (the day before Tisha B’Av) has all of the Laws of the Nine Days, but since it is so close to Tisha B’Av it takes on a few of the Laws of Tisha B’Av. For example, we may not play games on Erev Tisha B’Av, nor otherwise spend the time in diversions of leisure and pleasure.
The final meal on Erev Tisha B’Av is called the “Seudah Hamasekes”, the Separating Meal. The Seudah Hamasekes declares that this is the last thing we are eating before the fast begins. Nevertheless, it is permitted to eat after the Seudah Hamasekes until sunset. It is best, however, to declare out loud that you intend to eat after the Seudah Hamasekes, so that the Seudah Hamasekes should not constitute a formal acceptance or an oath that you will eat no more until after the fast.
The reason for the Seudah Hamasekes is to experience sorrow and mourning for the Destruction of the Holy Temple. Therefore, some practices of mourning apply to this meal as well, though not all.
Until we eat the Seudah Hamasekes, we may eat as much as we want, though we still may not eat meat or fowl, nor drink wine or grape juice. Before the Seudah Hamasekes we eat a full, regular meal, with those restrictions. Most people eat a full meal a few hours earlier, and eat the Seudah Hamasekes about half an hour before sunset.
The Seudah Hamasekes is eaten after praying Minchah (the Afternoon Services), but before the beginning of sunset. We must have finished the meal by the time sunset begins, that is, before the fast begins. However, we may say Birchat Amazon (the Blessings After the Meal) after the fast has begun.
We eat the Seudah Hamasekes while seated on the ground or on a low chair or cushion. We do not remove our leather shoes yet — that is done at sunset.
The Seudah Hamasekes consist only of bread, cold hard-boiled eggs, and water. Nothing else may be eaten or drunk. We may not drink beer or coffee.
A portion of the bread should be dipped in ashes and eaten. Before the Seudah Hamasekes I burn a napkin or paper plate, and drop the ashes into a bowl. Instead of dipping the bread into salt, as we are usually required to do at the beginning of a meal, we dip a piece of bread into the ashes.
Although we may not eat after the Seudah Hamasekes, we may sit on regular chairs or benches after the Seudah Hamasekes, until sunset, when Tisha B’Av and all its restrictions begins.