The fast of Asarah BeTevet is stricter than other fast days, and therefore, the Abudrahem says that even if it would theoretically fall on Shabbat, we would have to fast on Shabbat, like Yom Kippur. One of the reason for that is because it was the beginning of a lot of the tribulations of Am Yisrael. Nevuchadnetzar started his siege on that day, and after a year and six months, on the 17th of Tammuz, he breached the walls of Jerusalem.
The fast will start at 5:50 AM and it will end at 5:18 PM.
If one wants to eat or drink before Alot HaShachar (5:50) he needs to stipulate that he would like to do so. If he forgot to stipulate, for Sefardim he may drink, but not eat. For Ashkenazim, they can even eat. (Mishnah Berurah, Kaf HaChaim in Siman 564)
Here are some Halachot regarding Asarah BeTevet. Additionally, this year, Asarah BeTevet falls on Friday, and therefore there are certain leniences that apply.
It is a Mitzvah to take a hot shower on Friday, even according to those who are strict and hold that one is not allowed to on fast days. (Shulchan Aruch in Siman 550, Seif 2)
One is allowed to take a shower and go to the Mikveh, but he should be careful that water should not enter his mouth. (Shulchan Aruch ibid., Mishnah Berurah in Seif Katan 6)
One that is accustomed to taste the food on Friday to see if the food is good is allowed to taste the food, but he cannot swallow it, and one should not make a Bracha over it. (Shulchan Aruch in Siman 567, Seif 1)
One is allowed to take a haircut and cut his nails on Friday. (Rabbi Chaim Palaji in Siman 566, Seif 4)
The fast ends after Tze’et HaKochavim, but one cannot eat until after Kiddush, and it is therefore important to shorten Tefillah and to come on time. It is also suggested to sing Shalom Aleichem and Zemirot after Kiddush.
If the husband comes late and his wife and children are hungry waiting for him, they are allowed to make Kiddush for themselves.
One is allowed to brush his teeth or rinse his mouth if he is very sensitive and it is necessary for him. (Yabiah Omer)
There are many people that cannot break the fast on a heavy meal. It is permissible for them to make Kiddush and to drink a Revi’it (about 86 grams) and then they can drink tea or coffee and have some biscuits.
We will start Mincha at 4:00 PM instead of 4:15. We will read the Torah and have Birkat Cohanim.
For those that have the custom to wear Tefillin at Mincha, this year, they should not wear Tefillin at Mincha (Rabbi Chaim Palaji in his book Moed L’Kol Chai, Siman 29).
The Chief Rabbinate of Israel has designated this day as the day of Kaddish to commemorate all the unknown Jews that were murdered during the Holocaust. We also light candles for their Neshama.
Sick people, or anyone that has health issues is exempt from fasting. Women that are pregnant or nursing don’t need to fast. Otherwise, men and women, and those that reached the age of Mitzvot all equally need to fast on Asarah BeTevet.
May this day turn to be a day of Joy and happiness very soon with the coming of Mashiach. Wishing you all an easy and meaningful fast. Erev Shabbat Shalom.
Rabbi Tal