[Avodah] Fasting on a Yahrtzeit

[Prof. Levine]

I am posting my response on Avodah to R Micha's post on Areivim about
fasting on a yahrtzeit. YL

At 09:46 AM 1/24/2012, Micha wrote:
>On Mon, Jan 23, 2012 at 12:08:36PM -0500, Prof. Levine wrote:
>> At 09:51 AM 1/23/2012, SBA wrote:
>>> But the question remains, how come people who are generally makpid on
>>> sticking to halacha - ignore this one?

>> I have given up trying to figure out why people do or do not do this or
>> that.  YL
...

>    I think the taanis is minhag, not din.

The following is from page 418 of Mourning in Halacha

~ Fasting

24. It is a mitzvah to fast on the yahrzeit of one's father or mother. 54
In the Minchah prayer of the fast, one recites Aneinu ("Answer us ... ")
[in the blessing Shome'a tefillah "Who hears prayer")], as always during
an individual fast. 55

It is desirable to accept the fast upon oneself during the previous day's
Minchah prayer, in accord with the law of an individual fast. If one
forgot to do so, but one customarily fasts on the yahrzeit, one is still
required to fast. But if one does not customarily fast on this day, the
fast is not valid unless one accepted it upon oneself before sundown. 56

If one fasted on the first yahrzeit without stipulating that he did
not intend this practice to have the force of a vow, it is nevertheless
considered a vow. If one subsequently decides not to fast on the yahrzeit,
one must be released from the vow. 57

25. It is good to fast on the yahrzeit of one's primary teacher (rabbo
muvhak). since one is obligated to honor him even more than one's
father. 58

54. Rama (376:4 and 402:12); Shulchan Aruch (Orach Chaim 568:7). Some
suggest that one fasts on the yahrzeit because on that day one's maza/
(fortune) was bad (Maharam Mintz §9; Levush, Yoreh De'ah 402:12; Leket
Yosher p. 98, citing the author of Terumas HaDeshen). Others explain
that the fast is to gain atonement for one's parent, since every year
their soul undergoes a small amount of judgment (Maharam Mintz, §9;
Levush loc. cit.; Leket Yosher loc. cit.).

55. Kitzur Shulchan Aruch (loc. cit.).

56. Gesher HaChaim (32:6).

57. Chochmas Adam (171: 11); Kitzur Shulchan Aruch (221: 1); Gesher
HaChaim (loc. cit. par. 7).