- Question: [Tuesday, 19th Kisleiv 5782]
I just noticed that one of my Mezuzahs were upside down. I don’t know how this happened, but I must’ve absentmindedly put it in the wrong way into the case and only noticed now when I was looking for where the shin was, and saw it on the bottom. My question is did I fulfill the mitzvah until now, and should I replace it with a blessing?
If the parchment of the mezuzah was placed upside down onto the doorpost [ie. Shema on bottom, end of Vehaya facing up], then it is invalid and you are to recite a blessing when replacing it. Thus, if one entered the mezuzah into its case upside down, with the bottom [i.e. end of paragraph of Vehaya] facing opposite the Shin of the case, and placed the case with the shin facing up, then it is invalid.
To note, that this is an additional reason to have see-through mezuzah cases [in addition to other reasons mentioned in Shulchan Aruch] in order to be able to see that the mezuzah is top side up by being able to see the Shin of the parchment on top.
Explanation: Regarding the status of a Mezuzah that was placed upside down on the doorpost, we do not find any explicit discussion of this in the Talmud or Rishonim and Shulchan Aruch. What is discussed however is whether the mezuzah is to be placed in a vertical position or lying flat in a horizontal position. The Talmud states that a Mezuzah which was placed like a Nagar [door lock] is invalid. Now, the intent of this matter is under debate between Rashi and Rabbeinu Tam. Rashi holds that if it is placed in a lying position it is invalid, and therefore he holds that a Mezuzah must be placed in a vertical position standing up, and so is the ruling and custom of the Sephardim. However, Rabbeinu Tam rules that if it is placed in a vertical position, it is invalid being that such a position is demeaning as this is the way a donkey is buried, and hence in his opinion a Mezuzah is to be placed in a lying horizontal position. Now, although no one is accustomed to rule like this opinion of Rabbeinu Tam today, practically the Ashkenazi custom, as rules the Rama regarding the Medakdikin, is to place the mezuzah in a diagonal position to follow like both opinions, and have the mezuzah partially vertical as rules Rashi and partially horizontal as rules Rabbeinu Tam.
Now, all the above is in regard to vertical versus horizontal, however, no one discusses the law in the case it was put upside down. The first opinion that I found to discuss this matter is the Alter Rebbe in his Kuntrus Achron in Hilchos Tefillin in which he explains that an upside down mezuzah is invalid according to all opinions, both Rashi and Rabbeinu Tam. This is because it is considered a great belittlement to the mezuzah to have it placed upside down, and even Rashi agrees to this. According to this ruling, one is to recite a blessing when replacing it if it was found to be upside down as he did not fulfill the mitzvah. Many other Achronim likewise concord with this ruling of Admur although some disagree and hold that the mezuzah is nevertheless valid, and therefore some argue that it should be replaced without a blessing. Practically, those who follow the rulings of Admur should replace it with a blessing, and so rule majority of Poskim.
Sources: Poskim who rule an upside down mezuzah is invalid: Admur 32:70 Kuntrus Achron 15 “See Yoreh Deah 289 that even Bedieved it is invalid if placed lying according to Rashi, or erect according to Rabbeinu Tam due to Bizayon, and certainly [it is invalid] if placed upside down, and even Rashi agrees”; Daas Kedoshim 32:23 and Mikdash Me’at 32:101; 289:30 [is invalid due to being considered Lo Kisidran]; Miaseif Lekol Hamachanos 32:233; Biur Halacha 32:46 “Yihyeh” regarding Parshiyos of Tefillin that some Poskim hold it is Pasul even Bedieved [and the same would apply to a Mezuzah]; Kol Yaakov 32:46 regarding Tefillin rules like Admur; Kitzur Shulchan Aruch 11 Mileches Melachim Halacha Lemoshe 67 [is invalid and must recite new blessing]; Meoreir Yesheinim 172; Rivivvos Efraim 5:547 in name of many Rabbanim [replace with blessing]; Mishnas Hasofer 22:13 regarding tefillin; Chovas Hador 9:7; Mezuzos Beisecha in Shaar Hatziyon 289:62 and Pischei Mezuzos 27:6 [is invalid according to most Poskim, replace without a blessing]; See, Rav Chaim Kanievsk in Daati Noteh 584 and Mezuzoz Beisecha ibid that is valid and hence should be replaced without blessing; See regarding if a Mezuzah should be placed vertical or horizontal: Michaber and Rama and Tur Y.D. 289:6; Menachos 33a and Rashi and Tosafus there; Rama ibid that according to Rabbeinu Tam if placed vertical is invalid; Rama and Beis Yosef and Shach 289:9 that the custom of Sephardim is like Rash, and of Ashkenazim like compromise of both; Biur Hagr”a 289:14