The following rules apply to any year on which Tisha b'Av is observed on Sunday—whether it originally fell on Sunday or whether it fell on Shabbat and the fast was postponed until Saturday night.
On Shabbat, all public displays of mourning are strictly prohibited. On this day we eat, drink and rejoice as is customary—and even more so.
On this day we eat, drink and rejoice as is customary—and even more soThere are two exceptions: a) If Shabbat is actually the 9th of Av, then marital relations are forbidden.1 b) In all cases when Tisha b'Av is observed on Sunday, it is forbidden to study Torah starting with Shabbat midday (aside for those sections of Torah which are permitted to be studied on Tisha b'Av). As such, on this Shabbat we do not recite the chapter of Ethics of the Fathers as is the custom in many communities on summertime Shabbat afternoons.
No mournful "separation meal" is conducted before the fast. Instead, shortly before sunset we partake of a sumptuous and joyous pre-fast meal. Care must be taken, however, that this meal ends before sunset.
We sit on chairs of regular height and wear normal footwear until nightfall. Only washing, eating and drinking are prohibited starting with sunset.
Havdallah is recited on Sunday night.2 In the evening prayers, the usual Shabbat night insert of Atah Chonantanu is included. The prayer of Vihi No'am is omitted. Those who have not recited the evening prayers should say, before doing any activity that is forbidden on Shabbat, "Baruch hamavdil bein kodesh l'chol" ("Blessed is He who separates between the holy [day of Shabbat] and the mundane [weekday]").
Sometime on Saturday night, kindle the Havdallah candle and recite the appropriate blessing.
Immediately after the Barchu passage is recited in the Saturday night prayer service, remove your leather shoes and don non-leather footwear.
We sit on chairs of regular height and wear normal footwear until nightfallRecite the Havdallah on Sunday night before eating—omitting the blessings on the incense and candle. If possible, the Havdallah wine or grape juice should be given to a child – younger than bar/bat mitzvah age – to drink.
If the Ninth of Av falls on Shabbat, in which case the fast is delayed until the tenth, all the restrictions applicable to the Nine Days are observed on the night following the fast, but they do not extend into the following morning—the 11th of Av.