A Tale of Two Adars
This week, Klal Yisrael celebrated Rosh Chodesh Adar Rishon. As the month of Adar is the only one in the Jewish calendar that gets twinned (7 years out of every 19; in our calendar established millennia ago by Hillel II), every time such a leap year occurs, aside for the ‘Mishenichnas Adar’ celebrations, there is also some cause for concern and calculations.
Although the Gemara (Megillah 6b) concludes that all Purim-related observances (including the Arbah Parshiyos) are celebrated in Adar Sheini, to ensure that the Geulah (Redemption) from Haman (Purim) and the Geulah from Egypt (on Pesach) should be observed in consecutive months, nevertheless, figuring out in which Adar other life cycle events such as Bar Mitzvahs and Yahrtzeits should be observed, is quite complicated.
Who Is Truly Older?
It is widely known that adding a leap year into the mix always has interesting Bar Mitzvah-related ramifications. The majority consensus is that if a boy was born in a non-leap year, one which there was only one Adar, and on the year of his Bar Mitzvah there are two Adars, his Bar Mitzvah will occur in the second Adar, since it is considered the true one concerning when one becomes a man.
The same holds true if our lad was actually born in Adar Sheini. In fact, the only way one would celebrate a Bar Mitzvah in the first Adar is if he was actually born in an Adar Rishon. This is the accepted practical ruling by all authorities, both Ashkenazic and Sefardic.
This makes for a remarkable dichotomy. If one boy is born on the 21st of Adar Rishon, and his buddy a week and a half later on the 2nd of Adar Sheini, then in any standard year following, the second lad would be celebrating his birthday almost 3 weeks before his “older” friend. Since in a standard year there is only one Adar, the second-born’s birthday would be the 2nd of Adar, while his “older” friend’s would be several weeks later, on the 21st. In fact, only in a leap year would the older one truly be considered older. This would also affect their Bar Mitzvahs. If their Bar Mitzvah is in a standard year, the younger lad would become a man several weeks before his older compadre. Yet, if their Bar Mitzvahs also occur in a leap year, then the older stays the older and the younger stays the younger for Bar Mitzvah purposes as well.
Anecdotally, it is due to this classic calenderical conundrum canon that my daughter celebrated her Bas Mitzvah, becoming a woman on her 12th birthday, 13 months prior to her twin brother’s Bar Mitzvah!
Bar Mitzvah-ed Early
An additional fascinating upshot of all this is that even though the near-universal psak is that a Bar Mitzvah of a boy born in a standard Adar is celebrated in Adar Sheini, nonetheless, there are poskim, most notably the Beis Shlomo, who maintain that the Bar Mitzvah boy should start to lay Tefillin from Adar Rishon a month and a day before his actual Bar Mitzvah, even if his minhag is not to do so until the Bar Mitzvah itself. The reason is that according to the minority opinion of the Maharash Halevi, the ikar is the first Adar, and if one would start to lay Tefillin 30 days before his true Bar Mitzvah in Adar Sheini, people may mistakenly suspect that his actual Bar Mitzvah is that day in Adar Rishon, which is not the normative halachah. Thus, the early extra day of donning Tefillin serves as a hekker of sorts, a public message showcasing that that first day of wearing Tefillin is not the actual Bar Mitzvah. Additionally, since the common minhag is to start donning Tefillin prior to the Bar Mitzvah anyway, by adding the extra day (31 days), the bochur fulfills the minority opinion as well.
Several contemporary poskim, including Rav Shmuel Halevi Wosner zt”l and Rav Moshe Sternbuch, express preference for keeping this minhag of 31 days. In fact, the Tzitz Eliezer opines that it is for a leap year like this that the minhag to start laying Tefillin a month before their Bar Mitzvah developed. Just another tidbit to add additional calculations and complications to a year with double Adars.
Although a completely unknown shittah to most, this is the reason why my son who became Bar Mitzvah in a double Adar, started laying Tefillin 31 days before his actual Bar Mitzvah.
However, and quite interestingly, Yahrtzeit observance seems to be an entirely different story.
The Shulchan Aruch rules that if one’s parent passed away in a standard Adar his Yahrtzeit should be observed in Adar Sheini (similar to the accepted psak for a Bar Mitzvah). Yet, the Rema, citing the Terumas Hadeshen and Mahari Mintz, argues that Yahrtzeits do not share the same status as Bar Mitzvahs, and conversely they should be observed in Adar Rishon.
[Important Note: This machlokes does not apply regarding one who was actually niftar in an Adar Rishon or Adar Sheini; those Yahrtzeits are always observed on the exact day.]
Will the Real Adar Please Stand Up?
The Terumas Hadeshen posits that this machlokes is actually based on another one: between R’ Meir and R’ Yehuda (Nedarim 63a) concerning which Adar is considered the main one regarding the laws of Nedarim and Shtaros - Vows and Documents. The Rambam follows R’ Meir’s opinion, that Adar Sheini is considered the main one, while most other Rishonim, including the Rosh, Ritva, and Ran, follow R’ Yehuda (as is the general rule in Shas), that Adar Rishon is considered the main one. Apparently, regarding Yahrtzeits the Shulchan Aruch sides with the Rambam, while the Rema follows the opinions of the other Rishonim.
Another understanding of this machlokes is that it is based on conflicting Talmudic dictums. Since it is a mitzvah to properly observe a parent’s Yahrtzeit, would we not assert ‘Ain Maavirin al HaMitzvos’, not to let a mitzvah pass us by? If so, we certainly should attempt to do so as soon as possible, i.e. Adar Rishon, and not wait until Adar Sheini.
Yet, other authorities claim ‘Akdumei Paranusa Lo Mekadmin’, delaying observances that may cause anguish, might be more important here, as we find regarding Tisha B’Av and other fast days, that when a scheduling conflict arises, we delay the fast instead of observing it sooner. Similarly, since the accepted practice is to fast on a Yahrtzeit, they maintain that its observance should be delayed to Adar Sheini.
The Levush elucidates the Rema’s ruling, stressing a critical difference between Bar Mitzvahs and Yahrtzeits. As opposed to a Bar Mitzvah, when a child is now considered a man and obligated in Mitzvos, properly observing a Yahrtzeit actually achieves repentance (Kapparah) for the soul of the deceased. The Judgment of Gehinnom is twelve months, therefore immediately after the conclusion of this period, which, in a leap year would occur in the first Adar, we should observe the Yahrtzeit to obtain elevation for the Neshama. Why should we prolong his Kapparah? And once the Yahrtzeit is already observed in Adar Rishon, the first year after the passing, it is already set as the one to observe every time there is a leap year.
Yet, other authorities, including the Chasam Sofer, disagree, maintaining that although we find that regarding the laws of Nedarim and Shtaros, even the Shulchan Aruch concedes that Adar Rishon is considered the main Adar, even so, asserts that Yahrtzeits should nonetheless be observed in Adar Sheini. He explains that the rule regarding Nedarim and Shtaros is that they follow ‘lashon Bnei Adam’, the common vernacular. Since people are used to only calling the month Adar in a standard year, even in a leap year the first Adar is simply colloquially called Adar as well. Yet, concerning Yahrtzeits, which concerns Neshamos, its observance would follow the ‘lashon HaTorah’, which clearly establishes Adar Sheini as the main Adar, as all Purim-related observances are celebrated in Adar Sheini! Therefore, he concludes that Yahrtzeits should be observed in Adar Sheini.
Double Yahrtzeit ?
Generally speaking, the practical halacha here follows the traditional paths after the main halacha codifiers. Sefardim, who follow the psakim of the Shulchan Aruch, observe an Adar Yahrtzeit in Adar Sheini, while Ashkenazim would do so in Adar Rishon. Yet, there are several Ashkezaic poskim who rule like the Shulchan Aruch here, maintaining that a Yahrtzeit should be observed in Adar Sheini.
However, it is important to note that many of the authorities who rule that Yahrtzeit observance is in Adar Rishon, still do allow one to say Kaddish and / daven for the amud in Adar Sheini, especially if there is no other Chiyuv that day.
But, to make matters even more confusing, the Rema adds that there are those who maintain that Yahrzteits should be observed in both Adars (!!). Although in Hilchos Aveilus the Rema seems to have dropped this opinion as a viable option, nevertheless, it is a psak that several later authorities, including the Shach, Magen Avraham, and the Vilna Gaon, aver is required. In fact, and although the Aruch Hashulchan discounts this opinion, as this is not a matter of prohibition and therefore a chumra is non-applicable, still, the Mishna Berura writes that if possible one should try to observe the Yahrtzeit on both days.
The Adar Amud
So, what is one to do? He should ask his Rav and follow his local shul’s minhag. Forewarned is forearmed. Especially nowadays when ‘fights for the amud rights’ are unfortunately not that uncommon. It is always prudent to ascertain each individual shul’s minhag, as well as get permission, before approaching the amud.
During a previous double Adar, while in America for a simcha, this author noticed a highly commendable and helpful sign posted by the Rav, Rabbi Eytan Feiner, in the famed White Shul in Far Rockaway, with clear and concise instructions to enable easy Yahrtzeit observance during the months of Adar. It proclaimed that the shul follows Ashkenazic practice. Therefore, Yahrtzeit observance for one who was niftar in a regular Adar should be in Adar Rishon. If the mourner is Sefardi, he should observe the Yahrtzeit in Adar Sheini. If one’s minhag is to observe both Adars, he may do so, as long as it does not interfere with someone else’s actual Yahrtzeit (i.e. davening for the amud).
Yes, Mishenichnas Adar Marbin B’Simcha, but sometimes that simcha is reserved for resolving halachic doubt.
This article is based on a Hebrew ma’amar featured in this author’s M’shulchan Yehuda, published in honor of my son’s Bar Mitzvah.
This article was written l’Zechus for Shira Yaffa bas Rochel Miriam v’chol yotzei chalatzeha for a yeshua teikif umiyad and l’Refuah Sheleimah Shoshana Leah bas Dreiza Liba, Mordechai ben Sarah, and Shayna bas Fayga
For any questions, comments or for the full Mareh Mekomos / sources, please email the author: email@example.com.
Rabbi Yehuda Spitz serves as the Sho’el U' Meishiv and Rosh Chabura of the Ohr Lagolah Halacha Kollel at Yeshivas Ohr Somayach in Yerushalayim. He also currently writes a contemporary halacha column for the Ohr Somayach website titled “Insights Into Halacha”.http://ohr.edu/this_week/insights_into_halacha/.
 See Gemara Rosh Hashanah 7a and Gemara Sanhedrin 12b. There are several sevaros explaining why only Adar gets doubled. See Rashi (Rosh Hashanah ad loc. s.v. v’afap”ch), Tosafos (Sanhedrin ad loc. s.v. ein), Kedushas Levi (Parshas Ki Sisa s.v. ta’am), and Sfas Emes (Likutim L’Chodesh Adar).
 Mishnah Taanis and following Gemara (Ch. 4, Mishnah 6; 29a).
 Rema (Orach Chaim 55: 10; based on Shu”t Mahari Mintz 15), Levush (Orach Chaim 685, 1), Mogen Avrohom (Orach Chaim 55: 10), Pri Chodosh (ad loc. 10), Pri Megadim (ad loc. Eshel Avraham 10; he adds that m’pashtus this is also the Shulchan Aruch’s shitta), Levushei Srad (ad loc. s.v. eino), Korban Ha’eidah (on Yerushalmi Megillah Ch. 1, Shiyarei Hakorban s.v. hada), Shaarei Teshuva (Orach Chaim 55: 11), Gilyon Maharsha (Yoreh Deah 402, s.v. b’Adar), Kitzur Shulchan Aruch (15: 2), Aruch Hashulchan (Orach Chaim 55: 14), Mishnah Berurah (ad loc. 45), and Kaf Hachaim (ad loc. 59); not like the Maharash Halevi (or Mahrash L’Bais Halevi; Shu”t Orach Chaim 16) who was of the opinion that in such a case, all observances should be celebrated in Adar Rishon.
 Although the Magen Avraham (ibid., based on his understanding of the Mahari Mintz’s position) maintains that even a boy born in an Adar Rishon’s Bar Mitzvah gets deferred to Adar Sheini, and the Olas Hatamid and Chasam Sofer (Shu”t Orach Chaim 163: end 3) agree with him, nevertheless, the consensus of poskim is that one who is born in an Adar Rishon’s Bar Mitzvah is observed in Adar Rishon as well; if he was born in a standard Adar or Adar Sheini his Bar Mitzvah would be observed in Adar Sheini. These poskim include the Shulchan Aruch (ibid.), Levush (Orach Chaim 685: 1), Pri Chodosh (ad loc. 10; citing the Yerushami Megillah Ch. 1: 5, that Adar Rishon is merely a ‘tosefes’), Shvus Yaakov (Shu”t vol. 1: 9; who writes that the Mogen Avrohom misunderstood the Mahari Mintz), Elyah Rabbah (Orach Chaim 55: 9 and Elyah Zuta 5), Rav Dovid Oppenheim (cited in the Ba’er Heitiv ad loc. 11), Me’il Tzadaka (Shu”t 21), Shaarei Teshuvah (Orach Chaim 55: 11), Ma’amar Mordechai (ad loc. 13), Pri Megadim (ad loc. Eshel Avrohom 10), Ikrei Hadat (3: 7), Maharsham (Daas Torah ad loc. s.v. u’shnas), Kitzur Shulchan Aruch (15: 2), Aruch Hashulchan (Orach Chaim 55: 14), Mishnah Berurah (ad loc. 43), and Kaf Hachaim (ad loc. 59). The Ba’er Heitiv (ibid.) concludes that “v’chein haminhag pashut eitzel kol ba’alei hahora’ah”. On an anecdotal level, this halacha affected this author growing up, as my birthday was Rosh Chodesh Adar and my Bar Mitzvah occurred on a leap year. This also affected my son who was born on my birthday as well, as his Bar Mitzvah as his Bar Mitzvah was observed on Rosh Chodesh Adar Sheini 5776. [However, as an interesting counter-point, it had the opposite affect on his twin sister - as they were both born on Rosh Chodesh Adar Sheini and her Bas Mitzvah was on a standard Adar year. That means she reached the age of Mitzvos 13 months before her twin brother!]
 See Shu”t Beis Shlomo (Even Ha’ezer 56) who maintains that such an Adar Bar Mitzvah boy should be machmir to start laying Tefillin a month and a day prior to his actual Bar Mitzvah in Adar Sheini. Although not everyone follows his chiddush, it is cited by many poskim l’maaseh. See Shu”t Shevet Halevi (vol. 6: 9 and vol. 10: 105, 2), Shu”t Tzitz Eliezer (vol. 13: 10 s.v. ela and u’chyadua), Moadim U’Zmanim (vol. 7: 250 s.v. v’ch”z & u’la”d), Orchos Chaim (Spinka; 37), Igros Hakodesh (5717; vol. 14: 243, postscript), and Shu”t Lehoros Nosson (vol. 12: 5). Thanks are due to R’ Shloimie Lerner for pointing out and providing several of these invaluable sources.
 However, as opposed to this author who was born on a standard Adar but Bar Mitzvah-ed on an Adar Sheini, my son was actually born on Adar Sheini. Although practically there is no halachic difference between our birthdays and Bar Mitzvahs vis a vis their observance, there still might be one regarding the proper date of first donning the Tefillin. This is because at the end of his responsum on topic, the Maharash Halevi actually agrees to the Mahari Mintz in one specific case: if one is born on an Adar Sheini and the Bar Mitzvah is also on a leap year, then he would accede that the Bar Mitzvah should be celebrated in Adar Sheini. Accordingly, this would seem that although I should have first layed Tefillin 31 days prior to my Bar Mitzvah, nonetheless, my son would have no reason to, as the minority opinion agreed to the majority opinion in his exact case. However, there is another shittah the reader should be aware of - that of the Aruch La’Ner (Shu”t Binyan Tzion 151). He maintains that both days of Rosh Chodesh have a status of one day, meaning they are considered somewhat connected. Therefore, once our growing lad’s 13 years are complete and it is already Rosh Chodesh, he would already be considered a Bar Mitzvah, even though his true birthday is the following day (of Rosh Chodesh). The Aruch Hashulchan (Orach Chaim 55: end 15) implies this way as well, and this logic is also cited l’maaseh by the Vayaged Yaakov (Shemos, Mitzvosecha Sha’ashu’ai, Mitzvah 4) and his son the Vaya’an Yosef (Greenwald; Shu”t vol. 1: 33, 1 s.v. v’heishiv), and is mentioned in Ishei Yisroel (pg. 135, Ch. 15, footnote 26, in the parenthesis). Therefore, as my son was born on the second day of Rosh Chodesh Adar Sheini (a.k.a. the 1st of Adar Sheini), there is another relevant minority opinion that would need to be addressed, by making a hekker and being choshesh for. As such, and as most are unaware of the Maharash Halevi’s concession when the Bar Mitzvah bochur was born in Adar Sheini, the potential for mishap is still present. Therefore, due to these concerns, my son still first donned his Tefillin 31 days prior to his Bar Mitzvah, on the 30th of Shevat 5776, which was also known as the First Day of Rosh Chodesh Adar Rishon (at the Neitz Minyan at the Kosel Hamaaravi, if you must know).
 Shulchan Aruch and Rema (Orach Chaim 568: 7), Terumas Hadeshen (vol. 1: 294), Mahari Mintz (Shu”t 9). Interestingly, in his Beis Yosef commentary (end Orach Chaim 568), the Shulchan Aruch writes that that this opinion of such a Yahrtzeit being observed in Adar Sheini, is the ruling of the Mahari Weil (Shu”t Dinin V’Halachos 5; who was arguing on the Mahari Mulin).
 Terumas Hadeshen (vol. 1, 294). His assessment of the dispute is widely acknowledged as the proper one and is cited by many later authorities as a given.
 Application of this dispute includes if one writes a document listing only the month as Adar, which Adar was he referring to? The same applies to vows as well. If one made a Neder not to eat meat until Adar, until when is meat prohibited to him?
 Rambam (Hilchos Nedarim Ch. 10: 6; especially according to the Kesef Mishnah’s understanding ad loc.), Rosh, Ritva, and Ran in their commentaries to Nedarim 63a. Interestingly, Tosafos (Nedarim 63b s.v. v’hatanya) implies like the Rambam as well.
 See Shulchan Aruch (Yoreh Deah 402: 12).
 See Gemara Pesachim 64b, Yoma 33a, 58b, and 70a, Megillah 6b, and Menachos 64b. As the Terumas Hadeshen (vol. 1: 294) explains, although the Gemara Megillah (ibid.) ultimately decides that the ikar Adar follows Rav Shimon ben Gamliel’s opinion and it is deemed more important for Purim and its related Mitzos to be observed in the month adjacent to Pesach, nonetheless, in Rav Eliezer b’Rabbi Yosi’s minority opinion, the first Adar is ikar due to ‘Ain Maavirin al HaMitzvos’, and in his opinion one should fulfill Purim-related Mitzvos at the first opportunity and not wait until the second Adar. Hence, if this Mitzvah of Yahrtzeit observance (as per the Rema’s lashon ibid.) could technically be observed in either Adar, and being closer to Pesach is a non-applicable factor regarding Yahrtzeits, it stands to reason that it should preferably be observed in Adar Rishon due to this dictum. This should certainly hold true, especially as according to several authorities [see Nishmas Adam (13: 2; citing proof from Tosafos (Yoma 33a s.v. ain); thanks are due to Rav Yirmiyohu Kaganoff for pointing out these sources] this is actually a din Deoraysa, that when one has an opportunity to fulfill a Mitzvah sooner than another, one should not tarry, but should rather fulfill it as soon as one can. On the other hand, and although agreeing l’maaseh, the Maharil (Shu”t 31: 3; as pointed out by the Magen Avraham, Orach Chaim 568: 20) seems not to accept the dictum of ‘Ain Maavirin al HaMitzvos’ as the reason to mandate Yahrtzeit observance in Adar Rishon. The Machatzis Hashekel (Orach Chaim 568: 20 s.v. uv’teshuvas) opines that perhaps the Maharil is of the opinion that fasting for a Yahrtzeit is not due to the Mitzva of ‘Kibbud Av V’Eim’, but rather to protect him from ‘Mazal Ra’ah’ on the day one’s parent is niftar.
 See Gemara Megillah 5b, regarding pushing off Tishah B’Av. The Ramban (Milchemos Hashem; end of the first chapter of Megillah) adds that this applies as well to Taanis Esther. Although the Maharil (Shu”t 112) writes that this is inapplicable to a Yahrtzeit as it is only ‘Tzaara B’Alma’, nevertheless the Chasam Sofer reiterates this sevara several times. See Shu”t Chasam Sofer (Orach Chaim 163 s.v. v’hinei), Haghos Chasam Sofer on Shulchan Aruch (Orach Chaim 568: 7), and Chiddushei Chasam Sofer on Gemara (Megillah 5a). Thanks are due to Rav Yitzchak Breitowitz for pointing out this debate regarding Klalei HaShas to this author.
 See Levush (Orach Chaim 685: 1), Shu”t Beis Shlomo (Even Ha’ezer 56, Haghah M’ben Hamechaber 1), and Shu”t Har Tzvi (Orach Chaim vol. 2: 83, 1; quoting the Mahari Mintz).
 See Shu”t Chasam Sofer (Orach Chaim 163) and Haghos Chasam Sofer (to Orach Chaim 568: 7). The Vilna Gaon (Biur HaGr”a to Orach Chaim 568: 7 s.v. k’she’ira) cites this as well.
 Regarding Nedarim see Shulchan Aruch Yoreh Deah (220: 8); regarding Documents see Shulchan Aruch Choshen Mishpat (43: 28); regarding Gittin see Shulchan Aruch Even Ha’ezer (126: 7). In all of these cases he agrees that the halachah follows R’ Yehuda that one who writes/says ‘Adar’ is referring to Adar Rishon. These cases all follow ‘Lashon Bnei Adam’, the common vernacular. Interestingly, he does not follow the Rambam in these cases [see how the Chelkas Mechokek and Bais Shmuel (in their commentaries to Even Ha’ezer 126: 7) deal with this difficulty].
 Most Sefardic poskim follow the Shulchan Aruch and mandate observing this Yahrtzeit in Adar Sheini, including the Knesses Hagedolah (Orach Chaim 568, Haghos on Beis Yosef), Chida (Machazik Bracha ad loc. 8), Yafeh Lalev (vol. 2, ad loc. 4) and Rav Daniel Tirani (Ikrei Hadat 29: 4). See Kaf Hachaim (Orach Chaim 568: 76), Chazon Ovadia (Purim ppg. 32 - 34), and Rav Mordechai Eliyahu’s Darchei Halacha glosses to the Kitzur Shulchan Aruch (221: 3), all of whom state this unequivocally.
 Although Rav Yaakov Emden implies in his responsa (Shu”t Sheilas Ya’avetz vol. 1, 117) like the Rema, nonetheless, in his later Siddur (Siddur Ya’avetz pg. 375a), as well as in his Mor U’Ketziah (Orach Chaim 686 s.v. yesh) he concludes like his father, the Chacham Tzvi, that such a Yahrtzeit should be observed in Adar Sheini. As mentioned previously, the Chasam Sofer (Shu”t Orach Chaim 163 and Haghos to Orach Chaim 568: 7) and Korban Ha’eidah (on Yerushalmi Megillah Ch. 1, Shiyarei Hakorban s.v. hada) were major proponents of this, as well. The Melamed L’Hoyeel (Shu”t Orach Chaim 113: 1 & end 116) also follows the Chasam Sofer on this. Additionally, Rav Moshe Feinstein (Shu”t Igros Moshe Yoreh Deah vol. 3: 160, 1) implies that the ikar truly is Adar Sheini for Yahrtzeits, as it should be the same as Bar Mitzvahs, all rationale proving otherwise notwithstanding. [Rav Ovadia Yosef (Chazon Ovadia - Purim pg. 34), expresses a similar sentiment. However, l’halachah Rav Moshe holds that one should observe the Yahrtzeit in both Adars - see next footnote.] Yet, it must be stressed that most Ashkenazic poskim follow the Rema’s shittah and maintain that the Yahrtzeit should be observed in Adar Rishon. These include the Maharil (Shu”t 31), Mahari”i Mintz (ibid.), Terumas Hadeshen (ibid.), Levush (ibid.), Elyah Rabba (Orach Chaim 685, 7 & Elyah Zutah ad loc. 7), Taz (Orach Chaim 568: 3), Yeshuos Yaakov (ad loc. 4), Chayei Adam (132: 37), Kitzur Shulchan Aruch (221: 3), Aruch Hashulchan (Orach Chaim 568: 13 & 14), Maharam Brisk (Shu”t vol. 1: 128; who explains that the greatness of the Chasam Sofer notwithstanding, still the halacha here follows the Rema and most Ashkenazic poskim), Rav Yechiel Michel Tukachinsky (Gesher Hachaim Ch. 32: 10; who states that ‘rov’ Ashkenazim are noheg the first Adar), Rav Tzvi Pesach Frank (Shu”t Har Tzvi ibid.), Rav Shlomo Zalman Auerbach (Halichos Shlomo - Tefillah Ch. 18: 23 and Moadim vol. 1, Ch. 18: 11) and Rav Moshe Sternbuch (Moadim U’Zmanim vol. 7: end 250). The Mishnah Berurah (568: 42) as well, implies that regarding Yahrtzeits Adar Rishon is ikar. However, it is important to note that many of these authorities still do allow one to say Kaddish and / daven for the amud in Adar Sheini, especially if there is no other chiyuv that day.
 The Rema in Orach Chaim (568: 7) adds that there are those who are machmir to observe a Yahrtzeit in both Adars. Yet, in Yoreh Deah (402: 12), he repeats this halachah, while only mentioning that one should observe the Yahrtzeit in Adar Rishon! Nevertheless, several later authorities, including the Shach (Yoreh Deah 402: 11; quoting the Rashal and Bach) as well as the Mogen Avrohom (Orach Chaim 568: 20) and the Vilna Gaon (Biur HaGr”a to Orach Chaim 568: 7 s.v. shnayhem) hold that one must observe the Yahrtzeit in both Adars; the Gr”a even mandating it m’din. Although the Aruch Hashulchan (ibid.) writes strongly against what is essentially observing two distinct Yahrzteits for one person, nevertheless, the Mishnah Berurah (ad loc. 42), Rav Moshe Feinstein (Shu”t Igros Moshe Yoreh Deah vol. 3: 160, 1), and Rav Moshe Sternbuch (Moadim U’Zmanim (vol. 7: end 250) maintain that it is proper to observe a Yahrtzeit in both Adars if a parent was niftar in a standard Adar. However, even so, Rav Moshe Feinstein held that it is M’Toras Safek and not vaday, and therefore a vaday chiyuv on either Adar would maintain precedence for davening for the amud – see Mesores Moshe (pg. 193: 417). Rav Shlomo Zalman Auerbach (Halichos Shlomo ibid.), although writing that Adar Rishon is ikar for Yahrtzeits, nevertheless adds ‘yesh machmirim’ to daven for the amud in Adar Sheini. In the footnotes (Moadim ad loc. 38) it mentions that when his Rebbetzin was nifteres, Rav Shlomo Zalman made a public siyum for her Yahrtzeit in Adar Rishon and made another one ‘B’tzinah’ in Adar Sheini.
 Metzudas Dovid (Mishlei, Ch. 15: 30 s.v. me’ohr einayim) ‘Ha’aras Einayim B’Davar Hamesupak Yismach Lev Ki Ain B’Olam Simcha K’hataras Hasafeikos’! This saying is also cited by the Pri Megadim (Orach Chaim beg. 670, Eshel Avraham s.v. nohagin and Orach Chaim 682, Mishbetzos Zahav end 1) regarding why on Chanukah (as we say in Al Hanissim) it is fitting that the ‘Zeidim’ were given over to the ‘Oskei Torasecha’.
Disclaimer: This is not a comprehensive guide, rather a brief summary to raise awareness of the issues. In any real case one should ask a competent Halachic authority.
L'iluy Nishmas the Rosh HaYeshiva - Rav Chonoh Menachem Mendel ben R' Yechezkel Shraga, Rav Yaakov Yeshaya ben R' Boruch Yehuda, and l'zchus for Shira Yaffa bas Rochel Miriam and her children for a yeshua teikef u'miyad!