When Asarah BaTeves falls on Shabbos[1]
בן-אדם כתב-לך את-שם היום את-עצם היום הזה סמך מלך-בבל אל-ירושלם בעצם היום הזה
Son of Man, write for yourself the name of today. On this very day, the King of Babylonia began his siege on Jerusalem, on this very day[2]
Of the four minor fasts in commemoration of the destruction of Jerusalem and the Temple, the tenth of Teves is unique. This fast, which is in commemoration of the beginning of the siege on Jerusalem[3], is the only fast in our present calendar that can fall on a Friday[4]. It creates an unusual situation where we go into Shabbos having not eaten the entire day prior. Usually, a person shouldn’t go into Shabbos hungry[5]. This day is the exception. While this in fact happens this year, 5781, it’s also a very infrequent occurrence. Although it will happen again in two years, it’s been 20 years since it last happened. Something else that’s unique about the fast known as Asarah BaTeves is that in our present calendar, it cannot fall on Shabbos. The other fast days can. However, since it is forbidden to fast on Shabbos (besides Yom Kippur), they get pushed off until Sunday[6]. This situation doesn’t occur for Asarah BaTeves, as it cannot fall on Shabbos anyways.