Contrary to a popular misconception, the Three Weeks of mourning do not end with the conclusion of Tisha B’Av, but rather extend into the 10th of Av. In fact, there was once a custom to fast on both the 9th and 10th of Av1 and it seems that there were those who did so as recently as the 15th century,2 and perhaps even into the 17th century.3 Although there is no one today who fasts on both the 9th and 10th of Av “because we are too weak to do so,”4 a certain measure of mourning is observed on the 10th of Av.
There is much discussion as to exactly when the first Beit HaMikdash was destroyed. According to one account, it was destroyed on the 7th of Av5, while according to another account, it was destroyed on the 10th of Av.6 In order to reconcile this contradiction, the Talmud suggests that the Babylonians entered the Beit HaMikdash on the 7th of Av and went on a rampage that continued for three days. They then set fire to the Beit HaMikdash on the afternoon of the 9th of Av which continued to burn into the 10th of Av, culminating in its destruction.7
There is also some discussion as to when the second Beit HaMikdash was destroyed. According to the Talmud, it was destroyed on the 9th of Av,8 while according to Josephus, it was destroyed on the 10th of Av.9 Based on this and other considerations, there were Sages in the past who advocated moving the fast from the 9th of Av to the 10th.10 Indeed, although the fires were set on the 9th of Av, they were set late in the afternoon, and therefore most of the destruction of the Beit HaMikdash actually took place on the 10th of Av.11 If, for whatever reason, one did not fast on the 9th of Av, one should fast on the 10th and observe all the other Tisha B’Av restrictions, as well.12
According to the Shulchan Aruch, it is forbidden to eat meat or drink wine on the 10th of Av.13 Ashkenazi custom, however, is to observe these restrictions only until midday on the 10th of Av.14 The Bach suggests that on the 10th of Av one should only eat what is necessary, without indulging in treats, in order to recall that the 10th of Av should have been a fast day.15 So too, while there are authorities who permit one to cut one’s hair and do laundry immediately after the fast,16 common custom is not to do so until midday on the 10th of Av. Nevertheless, under extenuating circumstances, one may be lenient and do laundry immediately after the fast.17 One may also shower after the fast, should one feel the need to do so.18 Those who do not recite the “Shehecheyanu” blessing during the Three Weeks should not recite it on the 10th of Av either.19
When Tisha B’Av falls on Thursday, however, it is permitted to do any laundry that is needed for Shabbat immediately after the fast is over. One may also take a haircut after the fast, though some authorities advise waiting until Friday morning to do so, if possible. Nevertheless, eating meat, drinking wine, and listening to music remain prohibited until midday on Friday.20 When Tisha B’Av falls on Shabbat, and is pushed off to Sunday, all the restrictions of the Nine Days are lifted immediately after the fast, with the exception of eating meat and drinking wine.21 Some authorities rule that one should refrain from marital relations on the night of the 10th of Av unless it is the night of tevilla.22
There were those who kept some of the mourning restrictions for the entire month of Av! For example, Rav Papa was of the opinion that the ban against scheduling a court appearance with a non-Jew applies for the entire month of Av.23 So too, in some communities, weddings were not held the entire month of Av,24 or at least not until after Shabbat Nachamu.25 Indeed, there was a custom, observed by no less an authority than Rashi, to observe all the restrictions of the Nine Days until Shabbat Nachamu.26 Rav Yehuda was of the opinion that the prohibitions against doing laundry and taking a haircut continue for the entire month of Av as well.27 Nevertheless, the halacha is not in accordance with any of these views.28
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1 Yerushalmi, Taanit 4:6.
2 Beit Yosef, OC 558.
3 Magen Avraham 558:2.
4 Tur, OC 558.
5 Melachim II 25:8,9.
6 Yirmiyahu 52:10.
7 Taanit 29a.
8 Taanit 29a.
9 Josephus, Wars of the Jews 6:4:5.
10 Taanit 29a; Tosfot, Megilla 5b s.v. Ubikesh.
11 Taanit 29a; OC 558:1.
12 Birkei Yosef, OC 558.
13 Tur, OC 558; OC 558:1; Shaarei Teshuva 558:2; Yechaveh Daat 5:41.
14 Rema, OC 558:1; But see Shu”t Maharshal 92 who includes laundering, haircutting, and bathing, as well. Mishna Berura 558:3.
15 See also Mikraei Kodesh; Fasts 11:29.
16 OC 551:4.
17 Shemirat Shabbat K’hilchata 42:16; Piskei Teshuvot 558:2.
18 Teshuvot V’hanhagot 2:260.
19 Yosef Ometz 56; Machazik Bracha 558:2. See also Eishel Avraham (Butchatch) 558.
20 Magen Avraham 558:1; Aruch Hashulchan, OC 558:2; Mishna Berura 558:3; Shemirat Shabbat K’hilchata 42:52; Rivevot Ephraim 3:342. See also Be’er Moshe 3:79; Even Yisrael 7:27.
21 Rema, OC 558:1.
22 Mishna Berura 558:3; Kaf Hachaim, OC 558:7.
23 Taanit 29b.
24 Beit Yosef, OC 551; Magen Avraham 551:8.
25 Minchat Elazar 3:66.
26 Siddur Rashi; Machzor Vitri; Bach, OC 551. See also Taz, OC 551:10; Magen Avraham 551:16; Eliya Rabba 551:45. (Though, even according to this custom it is permitted to do laundry needed in honor of Shabbat)
27 Taanit 29b.
28 Taanit 30a; Mishna Berura 551:2.