There is a minhag for the firstborn to fast on Erev Pesach (Mechaber 470:1). When Pesach falls out on Motzei Shabbos like this year, Shabbos is Erev Pesach which is a time that it is prohibited to fast (Siman 288). The Mechaber (470:2) brings two opinions about what should be done. The first opinion holds that the fast is moved ahead to Thursday. Since it is already not in the proper time, it is better to have it on Thursday than Friday, which is Erev Shabbos. Still, Reb Nissim Karelitz zt”l says that if a bechor was unable to fast on Thursday, he should make up the fast on Erev Shabbos The second opinion holds that there is no fast at all. Since this fast is only a minhag, if it must be pushed off to another day, we don’t have it at all. The Rema says that the minhag is like the first opinion.
The Mishnah Berura says that many bechorim are lenient with this fast and partake in a seudas mitzvah thereby releasing themselves from their obligation to fast. Many even rely on a seudas siyum Masechta. Even though they themselves did not learn the Masechta they may still join the seuda. The minhag is that the mesayem ends the Masechta when everyone is gathered together and afterwards all the participants partake in the seuda.
The opinion of the Chavos Yair is that if one makes a siyum at night, the following day is included in the simcha. Reb Shmuel Wosner zt”l says that in a year like this one may rely on the Chavos Yair. Therefore if one has to be at work and he will not be able to participate in a siyum on Thursday, he can make a siyum on Wednesday night.
The Rema (686:2) says that, when Taanis Esther is moved up to Thursday, those who ate at the seuda of a bris Thursday morning must fast on Friday. Still, the Chazon Ish paskens that if a bechor ate at a seudas mitzvah on Thursday, he does not have to fast on Friday. The reason is that, first of all, Taanis Bechorim is only a minhag and, secondly, there is an opinion that there is no fast in such a year.
There are many who are careful to make two siyumim, one on Thursday and another on Friday. This was the minhag of the Steipler zt”l. Reb Moshe zt”l says that this is not necessary since the obligation to fast is on Thursday. This is also the psak of Rav Henkin zt”l. The Rema says that if a katan is a bechor and his father is not a bechor, his father fasts for him instead. The Steipler says that if the father participated in a siyum on Thursday he does not have to do so again on Friday.
Even those who would normally fast on a regular year and not rely on a siyum, in a year like this they may be lenient, since there is an opinion that there is no fast at all.
Some hold that in a year like this, if one cannot find a siyum to participate in, he may redeem it by giving tzedakah.1
Prepared by R’ Avrohom Yehoshua Ziskind
1Sources: Mishnah Berura, Dirshu, Piskei Teshuvos, Kovetz Halachos