Ta'anit Bechorotתַּעֲנִית בְּכוֹרוֹת

Fast of the Firstborn (Hebrew: תענית בכורות, Ta’anit B’khorot or תענית בכורים, Ta’anit B’khorim); is a unique fast day in Judaism which usually falls on the day before Passover. Usually, the fast is broken at a siyum celebration (typically made at the conclusion of the morning services), which, according to prevailing custom, creates an atmosphere of rejoicing that overrides the requirement to continue the fast. Unlike most Jewish fast days, only firstborns are required to fast on the Fast of the Firstborn. Ta'anit Bechorot, the Fast of the Firstborn, carries a theme of gratitude rooted in the tenth plague of the Exodus story (Makkat Bechorot). When the Egyptian firstborn died, the Israelite firstborn were spared, and firstborns fast as an act of thanksgiving and remembrance for that deliverance. What makes the day theologically distinctive is its narrow obligation: rather than calling the whole community to repentance like most fasts, it singles out firstborns as the recipients of a personal miracle. The earliest source, Tractate Soferim (21:3), frames it plainly as a fast "in commemoration of the miracle that they were saved." In practice it is also one of the most rarely completed fasts, since the prevailing custom allows firstborns to discharge the obligation by joining a siyum celebration rather than fasting the full day.

The fast falls on 14 Nisan, Erev Pesach, the day immediately before Passover begins at nightfall. The date is the same in Israel and the Diaspora; there is no scheduling difference between them. The fast technically runs from dawn (alot hashachar) until nightfall, though in practice it is broken in the morning after Shacharit. Rite-dependent variation appears only when Erev Pesach falls on Shabbat: since fasting on Shabbat is forbidden, the fast is moved earlier: the prevailing Ashkenazi custom shifts it to the preceding Thursday (12 Nisan), while many Sephardic communities consider it not obligatory and skip it. When Erev Pesach falls on a Friday, the fast is held that Friday. We recommend confirming the exact date and any shift for a given year against a current Jewish calendar.

There is no special Torah, Haftarah, or Megillah reading assigned to Ta'anit Bechorot, and no special cantillation or trope tied to the day. This sets it apart from other fasts: unlike Tisha B'Av (chanted with the distinctive Eicha trope) or public fast days (which use the "Vayechal Moshe" fast-day Torah reading from Exodus 32/34), Ta'anit Bechorot takes on none of the fast-day liturgy. Because it falls during Nisan and on Erev Pesach, penitential prayers are suppressed: Tachanun is omitted, and no Selichot, Avinu Malkeinu, or fast-day Torah reading is added. The morning service is essentially an ordinary Nisan weekday service; if it lands on a Monday or Thursday, the regular weekday Torah portion would be read with standard weekday trope.

The dominant custom is to break the fast at a siyum (the festive completion of a tractate of Talmud or an order of Mishnah) held after Shacharit on Erev Pesach. The resulting seudat mitzvah creates an atmosphere of rejoicing that exempts those present from continuing the fast, and cake and schnapps are typically shared afterward; most congregations arrange for the rabbi or a scholar to make such a siyum. The obligation falls only on firstborns (firstborn of the mother, and by many opinions firstborn of the father), including Kohanim and Levi'im. A father customarily fasts on behalf of a firstborn son below bar mitzvah age, though contemporary practice has softened on fasting for minors. Both the prevailing Ashkenazi and Sephardic custom is that women and firstborn daughters do not fast, and pregnant or nursing women do not fast regardless; some authorities (e.g., the Bach) held differently, and historically some Sephardic women fasted and likewise relied on the siyum exemption.