Explaining the Laws of the Three Weeks
Rabbi Kaganoff
Explaining the Laws of the Three Weeks
by Rabbi Yirmiyohu Kaganoff
The three-week period between Shiva Asar B’Tammuz and Tisha B’Av is kept by Klal Yisroel as a time of mourning. In this article, we will review and explain the halachos that apply during the Three Weeks. In a subsequent article, we hope to review the halachos that apply during the Nine Days that begin with Rosh Chodesh Av.
WHAT HAPPENED ON SHIVA ASAR B’TAMMUZ?
The Mishnah teaches us that five tragic events occurred on the 17th day of Tammuz:
1. The luchos (tablets) containing the Aseres Hadibros (The Ten Commandments) were destroyed.
2. The daily korbanos offered in the First Beis Hamikdosh were stopped (see Rambam, Hilchos Taanis 5:2).
3. The walls of the city of Yerushalayim were breached, leading to the destruction of the Second Beis Hamikdosh (Taanis 28b).
4. The wicked Apostomus, a Greek officer, burned the Torah near a bridge in Eretz Yisroel during the period of the second Beis Hamikdosh (see Talmud Yerushalmi and Tiferes Yisroel).
5. An idol was placed inside the Beis Hamikdosh. According to Rashi, this was done by the evil King Menashe in the time of the first Beis Hamikdosh. Others explain that this incident occurred during the Second Beis Hamikdosh time period (Rambam, Hilchos Taanis 5:2). These two interpretations reflect two opinions recorded in the Talmud Yerushalmi.
To commemorate these tragic events, the Jewish people observe the 17th of Tammuz as a fast day (see Rosh Hoshana 18b; Rambam, Hilchos Taanis 5:1-4). In addition, the custom developed to observe some mourning practices (aveilus) from this day until Tisha B’Av. This three-week season is referred to by Midrash Rabbah (Eicha 1:3) as the period of Bein Hametzorim.
It is noteworthy that neither the Mishnah nor the Gemara associate any mourning practices with the Bein Hametzorim period. Rather, the Mishnah mentions that the mourning of the Tisha B’Av season begins on Rosh Chodesh Av by “decreasing simcha” (Taanis 26b). The Mishnah does not explain what activities are curtailed in order to decrease simcha.
The Gemara (Yevamos 43a, as explained by the Ramban and Tur; cf. Rashi) refers to four activities that are prohibited during this period, presumably to manifest this decreasing of simcha:
1. Business activity is decreased. (There is a dispute among poskim what types of business activity are intended; see Mishnah Berurah 551:11.)
2. Construction and planting for a simcha are not done (Yerushalmi, Taanis, cited by Tosafos to Yevamos 43a s.v. Milisa).
3. Weddings are not conducted. An additional reason is cited to forbid weddings during these nine days; notably, that since this is not a good season for Jews, one should postpone a wedding to a more auspicious date (Beis Yosef 551; Magen Avrohom 551:8).
4. One may not make a festive meal to celebrate an eirusin. This was the approximate equivalent to our making a tenaim or vort to celebrate an engagement. The Gemara permits making the eirusin itself, provided one does not make a festive meal to celebrate it. It is permitted to become engaged during the Nine Days and even on Tisha B’Av itself! (Magen Avrohom 551:10; Tur, quoting Rav Nissim; Shulchan Aruch 551:2).
Although the Mishnah and Gemara make no mention of beginning the mourning period any earlier than Rosh Chodesh, accepted minhag Ashkenaz is to begin the aveilus from the 17th of Tammuz. Thus, the Rema (Darchei Moshe 551:5 and Hagahos 551:2) reports that Ashkenazim do not make weddings during the entire period of the Three Weeks, a practice that has become accepted by many Sefardic communities (Ben Ish Chai, Parshas Devorim #4; Knesses Hagedola). However, many Sefardic communities permit making a wedding until Rosh Chodesh Av, and under certain circumstances even later (Shu’t Yabia Omer 6:Orach Chaim #43 see also Sdei Chemed Vol. 5, pg. 279 #14, who states that it depends on the custom of the community).
MAY ONE SCHEDULE A VORT DURING THE THREE WEEKS?
It is permitted to celebrate an engagement during the Three Weeks, provided there is no music or dancing (Magen Avrohom 551:10). Until Rosh Chodesh one is allowed to celebrate the engagement with a festive meal (Mishnah Berurah 551:19), but from Rosh Chodesh one should serve only light refreshments (Magen Avrohom 551:10).
IS DANCING PERMITTED DURING THE THREE WEEKS?
Most dancing is prohibited during the Three Weeks (Magen Avrohom 551:10; Elyah Rabbah 551:6; Mishnah Berurah 551:16). However, there are poskim who permit dancing at a sheva brochos.
MAY ONE GET MARRIED ON THE NIGHT OF THE 17TH OF TAMMUZ?
When the 17th of Tammuz falls out during the week, one who chooses to get married on the night of the 17th should begin the wedding in the daytime of the 16th. There are poskim who contend that this is permitted only under extenuating circumstances (Piskei Tshuvos 551: 7 footnote 51).
When the 17th falls out on Sunday, and one cannot begin the wedding on the 16th, most poskim prohibit making a wedding on the night of the 17th (Motzei Shabbos), since they consider that the period of mourning begins already (Shu’t Tzitz Eliezer 10:26). Many poskim contend that the night of the 17th should be treated even more strictly than the Three Weeks; it should be treated with the stringencies of the Nine Days (Elyah Rabbah; Shu’t Chaim Sha’al #24; Biur Halacha 551:2). However, Rav Moshe Feinstein rules that, under extenuating circumstances, it is permitted to schedule a wedding on the Motzei Shabbos the night of the 17th of Tammuz (Shu’t Igros Moshe, Orach Chaim 1:168).
WHAT ARE THE LAWS ABOUT HAVING HAIRCUTS AND SHAVING DURING THE THREE WEEKS?
The Mishnah (Taanis 26b) rules that it is prohibited to cut one’s hair from Motzei Shabbos preceding Tisha B’Av until Tisha B’Av. (These days are referred to as “shavua shechal bo Tisha B’Av,” the week in which Tisha B’Av falls. We will refer to these days as “the week of Tisha B’Av.”) This includes both shaving one’s beard and getting a haircut (Ran). Thus, according to the takana of Chazal, it was permitted to have a haircut or shave up until a few days before Tisha B’Av. However, the Rema notes that the custom among Ashkenazim is that we do not cut our hair during the entire Three Weeks (Darchei Moshe 551:5 and Hagahos 551:4).
There are different customs among Sefardim whether to allow haircuts during the Three Weeks. Shulchan Aruch (551:3) rules that it is prohibited to have a haircut only in the week of Tisha B’Av, as is recorded in the Gemara, and this is the practice that is recorded by Rav Ovadia Yosef (Shu’t Yechaveh Daas 4:36). However, other Sefardic poskim record that it is dependent on custom (Ben Ish Chai, Parshas Devorim #12)
Rav Ovadia Yosef paskens that Sefardic bochurim learning in an Ashkenazic yeshiva are permitted to shave until Rosh Chodesh. Even though most of the students in the yeshiva follow the Ashkenazic practice of not shaving during the entire Three Weeks, it is permitted for the Sefardim to follow their custom and shave (Shu’t Yechaveh Daas 4:36). The general rule that a community should follow one halachic practice is true when the community has one rav or follows the guidance of one beis din. However, when the community has different rabbonim or different batei din, each community may follow its own halachically accepted practice (Yevamos 14a).
There are a few exceptions when Ashkenazim are permitted to shave or get a haircut during the Three Weeks. For example, it is permitted to trim one’s mustache if it interferes with eating (Ran; Shulchan Aruch 551:13).
Shu’t Chasam Sofer (Yoreh Deah #348 s.v. ve’i golach) rules that a person who shaves every day is permitted to shave on Friday during the Three Weeks in honor of Shabbos. Furthermore, he also implies that someone who is very uncomfortable because of his beard stubble is permitted to shave during the Three Weeks, except for the week of Tisha B’Av (see Shearim Hametzuyanim B’Halacha 122:5). Both of these rulings are controversial and one should not rely on them without receiving a psak from a rav.
Rav Moshe Feinstein paskens that one may shave during the Three Weeks if he may lose his job or may lose customers because he does not shave. Rav Moshe Feinstein contends that when the prohibition against shaving is only because of minhag (as it is prior to the week of Tisha B’Av), there is no minhag to prohibit shaving if he will suffer financially as a result. However, if he will only suffer embarrassment or harassment but no loss of income, he is required to remain unshaven.
On the other hand, in the week of Tisha B’Av shaving is prohibited because of a takanas chachomim that forbids shaving even if one suffers financial loss (Shu’t Igros Moshe, Choshen Mishpat 1:93 and Orach Chaim 4:102).
If a bris falls out during the Three Weeks, the father of the baby, the mohel, and the sandek (who holds the baby during the actual bris) are permitted to shave or have a haircut (Shu’t Chasam Sofer, Orach Chaim #158). The Chasam Sofer permits a haircut and shave even during the week of Tisha B’Av, whereas other poskim disagree and permit this only until the week of Tisha B’Av (Shu’t Noda B’Yehuda 1:28; Shaarei Tshuva; Sdei Chemed 5:278:3) or only until Rosh Chodesh (Ba’er Heiteiv 551:3). The Noda B’Yehuda takes strong issue with a practice wherein the celebrants would shave and get their hair cut the Friday before the bris. He rules that it is permitted only on the day of the bris itself, and not even the night before (Shu’t Noda B’Yehuda 1:28). According to some poskim, the kvatter and the sandek meumad (also called “amida lebrochos”) are also permitted to shave or have a haircut (Shearim Hametzuyanim B’Halacha, Kuntrus Acharon 120:8, based on Elyah Rabbah 551:27 and Beis Meir 551). However, most poskim do not permit them and restrict the heter of shaving and haircutting in honor of the bris to the mohel, sandek, and the father of the baby.
Adults may not give children a haircut during the week of Tisha B’Av (Shulchan Aruch 551:14). There is a dispute between poskim whether a minor may have a haircut during the part of the Three Weeks before Shabbos Chazon (the Shabbos before Tisha B’Av). Some poskim contend that since the prohibition against haircuts during these weeks is only a custom, children are not included in the custom (Mishnah Berurah 551:82, quoting Chayei Odom), whereas other poskim rule that children are included in the custom (Elyah Rabbah 551:28).
Although some poskim permit scheduling an upsheren (chalakah) during the Three Weeks, if that is when the child’s birthday is, the prevalent practice is to postpone the upsheren until after Tisha B’Av (Piskei Tshuvos 551:44).
Some recent poskim have suggested that a bar-mitzvah bochur who needs a haircut may have one during the Three Weeks, as long as it is not during the week of Tisha B’Av. Shearim Metzuyanim B’Halacha concludes that it is halachically better for the bar-mitzvah to have a haircut the day before he turns bar-mitzvah and rely on the opinion that a minor may have a haircut during the Three Weeks until the week of Tisha B’Av (Kuntrus Acharon 120:8).
There are different opinions among poskim whether a woman may have her hair cut during the Three Weeks. Mishnah Berurah rules that a woman may not have her hair cut during the week of Tisha B’Av. He suggests that it may be permitted for her to trim the hair on the temples (Mishnah Berurah 551:79). Many poskim rule that a woman may tweeze her eyebrows and perform similar cosmetic activities (see Shu’t Igros Moshe, Yoreh Deah 2:137; Halichos Beisah, Chapter 25, footnote 70).
MAY I CLIP MY FINGERNAILS DURING THE THREE WEEKS?
It is permitted to clip one’s fingernails before the week of Tisha B’Av according to all opinions. It is a dispute whether one is allowed to clip nails during the week of Tisha B’Av (Magen Avrohom, 551:11 permits, whereas Taz 551:13 and Elyah Rabbah 551:7 prohibit).
WHAT ARE THE HALACHOS ABOUT PLAYING AND LISTENING TO MUSIC DURING THE THREE WEEKS?
Playing or listening to music for enjoyment is prohibited during the Three Weeks (Shu’t Igros Moshe, Orach Chaim Vol. 4:21:4). Poskim prohibit listening even to tape-recorded music (Shu’t Tzitz Eliezer 15:33).
Until the week of Tisha B’Av, it is permitted to play music for non-Jews for parnasa or to teach music for parnasa (Biur Halacha to 551:2 s.v. Memaatim, based on Pri Megadim). Similarly, it is permitted to take music lessons that are for parnasa. Some poskim permit taking lessons if the lessons are not for pleasure and there will be a loss of skill because of the length of time between lessons (Shu’t Tzitz Eliezer 16:19). However, the Kaf HaChaim (551:41) writes: “Those who teach music during these days should teach sad songs, and it would be even better if they did not teach any music at all.”
IS SINGING PERMITTED DURING THE THREE WEEKS?
Sdei Chemed discusses this shayla (Volume 5, page 376:10). He feels it is permitted, but quotes sources who seem to forbid it, and therefore is inconclusive. It is permitted to sing sad or moving songs, similar to what we sing on Tisha B’Av. Since it is uncertain that it is prohibited, one need not tell someone who is singing that he is doing something halachically wrong.
SHEHECHIYANU: MAY ONE RECITE THIS BROCHA DURING THE THREE WEEKS?
There are three opinions among the poskim:
- Shehechiyanu should not be recited during the Three Weeks, even on Shabbos (Arizal)
- Shehechiyanu should not be recited on weekdays but may be recited on Shabbos (Sefer Chassidim #840)
- Shehechiyanu may be recited even on weekdays (Taz and Gra 551:17).
Most halachic authorities rule like the middle opinion, permitting shehechiyanu to be recited on Shabbos but not on weekdays (Magen Avrohom, Elyah Rabbah, Chayei Odom; Mishnah Berurah). In general, laws of mourning do not apply on Shabbos; thus, shehechiyanu may be recited on Shabbos. (Rav Akiva Eiger rules that shehechiyanu may also be recited on Rosh Chodesh.)
An alternative approach to explain this opinion contends that it is a mitzvah to benefit from the world and make a shehechiyanu. Fulfilling the mitzvah supersedes the problem of reciting shehechiyanu during the Three Weeks—but it is appropriate to push it off to Shabbos (Mekor Chessed commentary to Sefer Chassidim #840, based on Yerushalmi at end of Kiddushin).
According to the Ari, the reason for not saying a shehechiyanu is not on account of the mourning itself but because it is inappropriate to recite a blessing that we should be rejuvenated to this time, which is a very inauspicious period. This reason not to recite shehechiyanu applies even on Shabbos (Magen Avrohom; Shu’t Chaim Sha’al #24).
The Gra contends that there is no halachic source that prohibits a mourner from reciting shehechiyanu. Apparently, he also does not agree with the reason attributed to the Ari.
MAY ONE RECITE SHEHECHIYANU THE NIGHT OF THE 17TH?
Most poskim hold that one should not (Shu’t Chaim Sha’aol #24; Sedei Chemed Vol. 5, pg. 277; Biur Halacha 551:2). However, Rav Moshe Feinstein contends that the mourning period does not start until morning, implying that one may recite a shehechiyanu at night (Shu’t Igros Moshe, Orach Chaim 1:168).
MAY A CHILD RECITE SHEHECHIYANU DURING THE THREE WEEKS?
This depends on the age and maturity of the child. If the child is old enough to appreciate the aveilus that is observed, then the child be trained not to say shehechiyanu during the Three Weeks. However, if he or she is not old enough to appreciate the aveilus, but is old enough to recite the shehechiyanu, one may allow him or her to recite the shehechiyanu (Birkei Yosef 551:9). There is no need to be concerned that the child is wishing this season to return.
Mishnah Berurah (511:99) permits a pregnant woman or an ill person to eat a new fruit without reciting the shehechiyanu.
According to all opinions, one recites a shehechiyanu when performing the mitzvos of pidyon haben or bris mila (for those who recite a shehechiyanu at a bris). Rema rules that one may also recite a shehechiyanu on a new fruit that will not be available after Tisha B’Av. Otherwise, one should wait until after Tisha B’Av to eat the fruit or to buy the clothing on which one would recite a shehechiyanu. It is permitted to purchase clothes that do not require a shehechiyanu.
MAY ONE PURCHASE A NEW CAR DURING THE THREE WEEKS?
Rav Moshe Feinstein rules that if the car is being purchased for pleasure or convenience, one should wait until after the Three Weeks to buy it. If, however, it is necessary for parnasa one may purchase it during the Three Weeks, but one should not recite the shehechiyanu until after the Three Weeks (Shu’t Igros Moshe, Orach Chaim 3:80). Some poskim permit buying any necessary appliance, such as a refrigerator, washing machine, or bed, to replace one that broke during the Three Weeks (Piskei Tshuvos 551:11).
OTHER HALACHOS OF THE THREE WEEKS
One should not engage in dangerous activities during the Three Weeks (see Shulchan Aruch, Orach Chaim 551:18). For this reason, some follow the practice not to schedule elective surgery until after Tisha B’Av (Piskei Tshuvos 551:1).
It is permitted to bathe, shower, go swimming, or go to the beach between the 17th of Tammuz and Rosh Chodesh Av, even if one has not gone swimming yet this season. Although people say that one may not go swimming for the first time during the Three Weeks, there is no halachic source for this practice. It is therefore not considered a binding custom and it is permitted without hataras nedorim (Tshuvos V’Hanhagos 2:263).
There are stringent opinions that forbid tiyulim, trips to the beach, and other entertaining activities during the Three Weeks (see Sedei Chemed, Vol. 5, pg. 376:10). Some poskim suggest that one should not swim in dangerous places or in water deeper than one’s height (Tshuvos V’Hanhagos 2:263).
FOCUS OF THE THREE WEEKS
The most important aspect of the Three Weeks is to focus on the tremendous loss we suffer because of the destruction of the Beis Hamikdosh. Tzaddikim make a point of reciting every night the tikkun chatzos, wherein we mourn the golus of the Shechina.
The minhag among Sefardic kehillos in Yerushalayim is to sit on the floor each day of the Three Weeks, just after midday, and recite part of tikkun chatzos and thereby mourn our loss. To further convey this mood, Yesod V’Shoresh HaAvodah prohibits any laughing and small talk during these weeks, just as a mourner does not engage in laughter or small talk (Shaar 9, Ch. 11-12).
Although we may not be holding on such a madreiga, we certainly should contemplate the tremendous loss in our spiritual lives that results from not having the Beis Hamikdosh. Let us pray intently for the restoration of the Beis Hamikdosh and the return of the Divine Presence to Yerushalayim, speedily in our days!
Rabbi Kaganoff
Explaining the Laws of the Three Weeks
by Rabbi Yirmiyohu Kaganoff
The three-week period between Shiva Asar B’Tammuz and Tisha B’Av is kept by Klal Yisroel as a time of mourning. This article will review and explain the halachos that apply during the Three Weeks.
WHAT HAPPENED ON SHIVA ASAR B’TAMMUZ?
The Mishnah teaches us that five tragic events occurred on the 17th day of Tammuz:
1. The luchos (tablets) containing the Aseres Hadibros (The Ten Commandments) were destroyed.
2. The daily korbanos offered in the First Beis Hamikdosh were stopped (see Rambam, Hilchos Taanis 5:2).
3. The walls of the city of Yerushalayim were breached, leading to the destruction of the Second Beis Hamikdosh (Taanis 28b).
4. The wicked Apostomus, a Greek officer, burned the Torah near a bridge in Eretz Yisroel during the period of the second Beis Hamikdosh (see Talmud Yerushalmi and Tiferes Yisroel).
5. An idol was placed inside the Beis Hamikdosh. According to Rashi, this was done by the evil King Menashe in the time of the first Beis Hamikdosh. Others explain that this incident occurred during the Second Beis Hamikdosh time period (Rambam, Hilchos Taanis 5:2). These two interpretations reflect two opinions recorded in the Talmud Yerushalmi.
To commemorate these tragic events, the Jewish people observe the 17th of Tammuz as a fast day (see Rosh Hoshana 18b; Rambam, Hilchos Taanis 5:1-4). In addition, the custom developed to observe some mourning practices (aveilus) from this day until Tisha B’Av. This three-week season is referred to by Midrash Rabbah (Eicha 1:3) as the period of Bein Hametzorim.
It is noteworthy that neither the Mishnah nor the Gemara associate any mourning practices with the Bein Hametzorim period. Rather, the Mishnah mentions that the mourning of the Tisha B’Av season begins on Rosh Chodesh Av by “decreasing simcha” (Taanis 26b). The Mishnah does not explain what activities are curtailed in order to decrease simcha.
The Gemara (Yevamos 43a, as explained by the Ramban and Tur; cf. Rashi) refers to four activities that are prohibited during this period, presumably to manifest this decreasing of simcha:
1. Business activity is decreased. (There is a dispute among poskim what types of business activity are intended; see Mishnah Berurah 551:11.)
2. Construction and planting for a simcha are not done (Yerushalmi, Taanis, cited by Tosafos to Yevamos 43a s.v. Milisa).
3. Weddings are not conducted. An additional reason is cited to forbid weddings during these nine days; notably, that since this is not a good season for Jews, one should postpone a wedding to a more auspicious date (Beis Yosef 551; Magen Avrohom 551:8).
4. One may not make a festive meal to celebrate an eirusin. This was the approximate equivalent to our making a tenaim or vort to celebrate an engagement. The Gemara permits making the eirusin itself, provided one does not make a festive meal to celebrate it. It is permitted to become engaged during the Nine Days and even on Tisha B’Av itself! (Magen Avrohom 551:10; Tur, quoting Rav Nissim; Shulchan Aruch 551:2).
Although the Mishnah and Gemara make no mention of beginning the mourning period any earlier than Rosh Chodesh, accepted minhag Ashkenaz is to begin the aveilus from the 17th of Tammuz. Thus, the Rema (Darchei Moshe 551:5 and Hagahos 551:2) reports that Ashkenazim do not make weddings during the entire period of the Three Weeks, a practice that has become accepted by many Sefardic communities (Ben Ish Chai, Parshas Devorim #4; Knesses Hagedola). However, many Sefardic communities permit making a wedding until Rosh Chodesh Av, and under certain circumstances even later (Shu’t Yabia Omer 6:Orach Chaim #43 see also Sdei Chemed Vol. 5, pg. 279 #14, who states that it depends on the custom of the community).
MAY ONE SCHEDULE A VORT DURING THE THREE WEEKS?
It is permitted to celebrate an engagement during the Three Weeks, provided there is no music or dancing (Magen Avrohom 551:10). Until Rosh Chodesh one is allowed to celebrate the engagement with a festive meal (Mishnah Berurah 551:19), but from Rosh Chodesh one should serve only light refreshments (Magen Avrohom 551:10).
IS DANCING PERMITTED DURING THE THREE WEEKS?
Most dancing is prohibited during the Three Weeks (Magen Avrohom 551:10; Elyah Rabbah 551:6; Mishnah Berurah 551:16). However, there are poskim who permit dancing at a sheva brochos.
MAY ONE GET MARRIED ON THE NIGHT OF THE 17TH OF TAMMUZ?
When the 17th of Tammuz falls out during the week, a wedding planned for the night of the 17th should begin the wedding in the daytime of the 16th. There are poskim who contend that this is permitted only under extenuating circumstances (Piskei Tshuvos 551: 7 footnote 51).
When the 17th falls out on Sunday, and one cannot begin the wedding on the 16th, most poskim prohibit making a wedding on the night of the 17th (Motzei Shabbos), since they consider that the period of mourning begins already (Shu’t Tzitz Eliezer 10:26). Many poskim contend that the night of the 17th should be treated even more strictly than the Three Weeks; it should be treated with the stringencies of the Nine Days (Elyah Rabbah; Shu’t Chaim Sha’al #24; Biur Halacha 551:2). However, Rav Moshe Feinstein rules that, under extenuating circumstances, it is permitted to schedule a wedding on Motzei Shabbos the night of the 17th of Tammuz (Shu’t Igros Moshe, Orach Chaim 1:168).
WHAT ARE THE LAWS ABOUT HAVING HAIRCUTS AND SHAVING DURING THE THREE WEEKS?
The Mishnah (Taanis 26b) rules that it is prohibited to cut one’s hair from Motzei Shabbos preceding Tisha B’Av until Tisha B’Av. (These days are referred to as “shavua shechal bo Tisha B’Av,” the week in which Tisha B’Av falls. We will refer to these days as “the week of Tisha B’Av.”) This includes both shaving one’s beard and getting a haircut (Ran). Thus, according to the takana of Chazal, it was permitted to have a haircut or shave up until a few days before Tisha B’Av. However, the Rema notes that the custom among Ashkenazim is that we do not cut our hair during the entire Three Weeks (Darchei Moshe 551:5 and Hagahos 551:4).
There are different customs among Sefardim whether to allow haircuts during the Three Weeks. Shulchan Aruch (551:3) rules that it is prohibited to have a haircut only in the week of Tisha B’Av, as is recorded in the Gemara, and this is the practice that is recorded by Rav Ovadia Yosef (Shu’t Yechaveh Daas 4:36). However, other Sefardic poskim record that it is dependent on custom (Ben Ish Chai, Parshas Devorim #12)
Rav Ovadia Yosef paskens that Sefardic bochurim learning in an Ashkenazic yeshiva are permitted to shave until Rosh Chodesh. Even though most of the students in the yeshiva follow the Ashkenazic practice of not shaving during the entire Three Weeks, it is permitted for the Sefardim to follow their custom and shave (Shu’t Yechaveh Daas 4:36). The general rule that a community should follow one halachic practice is true when the community has one rav or follows the guidance of one beis din. However, when the community has different rabbonim or different batei din, each community may follow its own halachically accepted practice (Yevamos 14a).
There are a few exceptions when Ashkenazim are permitted to shave or get a haircut during the Three Weeks. For example, it is permitted to trim one’s mustache if it interferes with eating (Ran; Shulchan Aruch 551:13).
Shu’t Chasam Sofer (Yoreh Deah #348 s.v. ve’i golach) rules that a person who shaves every day is permitted to shave on Friday during the Three Weeks in honor of Shabbos. Furthermore, he also implies that someone who is very uncomfortable because of his beard stubble is permitted to shave during the Three Weeks, except for the week of Tisha B’Av (see Shearim Hametzuyanim B’Halacha 122:5). Both of these rulings are controversial and one should not rely on them without receiving a psak from a rav.
Rav Moshe Feinstein paskens that one may shave during the Three Weeks if he may lose his job or may lose customers because he does not shave. Rav Moshe Feinstein contends that when the prohibition against shaving is only because of minhag (as it is prior to the week of Tisha B’Av), there is no minhag to prohibit shaving if he will suffer financially as a result. However, if he will only suffer embarrassment or harassment but no loss of income, he is required to remain unshaven.
On the other hand, in the week of Tisha B’Av shaving is prohibited because of a takanas chachomim, which forbids shaving even if one suffers financial loss (Shu’t Igros Moshe, Choshen Mishpat 1:93 and Orach Chaim 4:102).
If a bris falls out during the Three Weeks, the father of the baby, the mohel, and the sandek (who holds the baby during the actual bris) are permitted to shave or have a haircut (Shu’t Chasam Sofer, Orach Chaim #158). The Chasam Sofer permits a haircut and shave even during the week of Tisha B’Av, whereas other poskim disagree and permit this only until the week of Tisha B’Av (Shu’t Noda B’Yehuda 1:28; Shaarei Tshuva; Sdei Chemed 5:278:3) or only until Rosh Chodesh (Ba’er Heiteiv 551:3).
Some poskim permit a haircut or shave only on the day of the bris itself (Shu’t Noda B’Yehuda 1:28). According to some poskim, the kvatter and the sandek meumad (also called “amida lebrochos”) are also permitted to shave or have a haircut (Shearim Hametzuyanim B’Halacha, Kuntrus Acharon 120:8, based on Elyah Rabbah 551:27 and Beis Meir 551). However, most poskim do not permit them and restrict the heter of shaving and haircutting in honor of the bris to the mohel, sandek, and the father of the baby.
Adults may not give children a haircut during the week of Tisha B’Av (Shulchan Aruch 551:14). There is a dispute between poskim whether a minor may have a haircut during the part of the Three Weeks before Shabbos Chazon (the Shabbos before Tisha B’Av). Some poskim contend that since the prohibition against haircuts during these weeks is only a custom, children are not included in the custom (Mishnah Berurah 551:82, quoting Chayei Odom), whereas other poskim rule that children are included in the custom (Elyah Rabbah 551:28).
Although some poskim permit scheduling an upsheren during the Three Weeks, if that is when the child’s birthday is, the prevalent practice is to postpone the upsheren until after Tisha B’Av (Piskei Tshuvos 551:44).
Some recent poskim have suggested that a bar-mitzvah bochur who needs a haircut may have one during the Three Weeks, as long as it is not during the week of Tisha B’Av. Shearim Metzuyanim B’Halacha concludes that it is halachically more acceptable for the bar mitzvah to have a haircut the day before he turns bar mitzvah and rely on the opinion that a minor may have a haircut during the Three Weeks until the week of Tisha B’Av (Kuntrus Acharon 120:8).