Kitzur Shulchan Aruch Chapter 11 Paragraph 4
The Laws of Mezuzah
סעיף ד שְׁנֵי בָתִּים אֲשֶׁר לְכָל אֶחָד יֵשׁ פֶּתַח לִרְשׁוּת הָרַבִּים אוֹ לֶחָצֵר, וּבַמְּחִיצָה אֲשֶׁר בֵּינֵיהֶם יֵשׁ גַּם לְכָל אֶחָד פֶּתַח לִרְשׁוּת הָרַבִּים אוֹ לֶחָצֵר, וּבַמְּחִיצָה אֲשֶׁר בֵּינֵיהֶם יֵשׁ גַּם כֵּן פֶּתַח, וְהַשְּׁתָּא יֵּשׁ לְהִסְתַּפֵּק בְּפֶתַח זֶה בְּאֵיזֶה צַד יִתֵּן אֶת הַמְּזוּזָה אָזְלֵינַן בָּזֶה בָּתַר הֶכֵּר צִיר. פֵּרוּשׁ, בִּמְקוֹם שֶׁנַּעֲשִׂים הַצִּירִים לְהַדֶּלֶת שֶׁהַדֶּלֶת נִפְתַּחַת לְתוֹכוֹ, זֶהוּ עִקַּר הַבָּיִת, וְנוֹתְנִים אֶת הַמְּזוּזָה בְּצַד הַיָּמִין שֶׁנִּכְנָסִים לְתוֹכוֹ. וְדַוְקָא כְּשֶׁשְּׁנֵי הַבָּתִּים שָׁוִים בְּתַשְׁמִישָׁם. אֲבָל אִם אֶחָד הוּא עִקַּר תַּשְׁמִישׁוֹ, בָּזֶה לֹא אָזְלֵינַן בָּתַר הֶכֵּר צִיר, אֶלָּא לְעוֹלָם נוֹתְנִין אֶת הַמְּזוּזָה בְּצַד הַיָּמִין שֶׁנִּכְנָסִים לְהַבַּיִת אֲשֶׁר עִקַּר תַּשְׁמִישׁוֹ שָׁם, אֲפִלּוּ הַדֶּלֶת נִפְתַּחַת לְתוֹךְ הַשֵּׁנִי
Kitzur 4. When there are two rooms, each room with a doorway opening onto a street or a courtyard, and in the wall between the rooms there is also a doorway, the proper mezuzah placement on the doorway between the two rooms is unclear. The determining factor in this regard is the “indication from the hinge,” that is: the side where the hinges are attached and towards which the door opens. This is considered the primary room, and we affix the mezuzah on the right side of one who enters that room.
The above applies only when the two rooms are used equally. However, if one of the rooms is more actively used, in that case, we are not guided by the “indication from the hinge.” Rather, the mezuzah must be affixed on the right as one enters the room more actively used, even if the door opens into the other room.
General Principles of Right-Hand Mezuzah Placement
The Torah commands us to place a mezuzah on the right doorpost as we enter a room or a gate. Even if all the dwellers in the home are left-dominant, the mezuzah is placed on what would be called the “right” for most people.
This requirement generally poses no problem when affixing the mezuzah to the main entrance of the house. However, determining the proper placement of mezuzot on interior rooms which are accessible from several entrances can be quite daunting.
Whenever possible, a rabbi should make these determinations as there are many factors that must be considered, and a mezuzah placed in error on a left doorpost is invalid. In most cases, a misplaced mezuzah must be transferred to the correct post and a new berachah recited. However, if a rabbi does not say that the present position is incorrect, but rather suggests that it is preferable halachically to move it to the other post, a new berachah is not necessary.
Determining Right-Hand Placement in Doubtful Situations
The details of this important halachic determination are many, and preferably a rabbi should be consulted in cases of doubt. Nevertheless, the following order of priorities can be followed as a general guideline.
- Priority 1 – Internal
- Priority 2 – Main entrance
- Priority 3 – Main room
- Priority 4 – Indication from hinge
Priority One — Internal
If a room has only one entrance, it is obvious that the mezuzah is placed on the right side of one going into that room.
This is true even if the door of the room is hinged so that it opens into the external room. The direction of the door’s swing is not enough of an indication to negate the fact that the doorway is an entrance to the inner room.
This is also true even if the inner room is used much less than the outer room. For example, if a formal dining room, used on rare occasions, is accessed only by walking through a busy family room, the mezuzah is nonetheless placed on the right of one going into the dining room.
Priority Two — Main Entrance
Often rooms can be accessed from more than one door, and therefore one of them cannot be defined as internal to the other. The doorway between two such rooms can be looked at as both an entrance and an exit from the one to the other. In these cases, one assesses the direction that people primarily take when going from one room to the other and places the mezuzah on the right of one going in that direction.
For example, a bedroom may have a second door from the garden, which is used from time to time. Coming from the garden, the main bedroom door is then also an entrance into a hall as much as it is an entrance into the bedroom. Nevertheless, since one generally enters from the hall into the bedroom from its main door, the mezuzah is placed on the right post of that entrance, going in.
Priority Three — Main Room
When none of the rooms is more internal than the other, and the primary direction of traffic between them is equal, we then look at the quantity of time spent in each of the rooms. The room one occupies the most is then called the “main” room, and the less used room is thought to lead into it. One places the mezuzah on the right side of the entrance to the “main” room.
For example, mezuzot are placed on the right of corridor doors which lead into the rooms that they service. This is true even if those rooms are not considered more internal than the corridor as they can be accessed from another door. It is also true even if the doors swing into the corridor.
Priority Four — Indication from the Hinge
In Talmudic times, doors were not set into the doorways but rather hinged on the inside of the room, so they could not be tampered with from the outside. As such, the position of the hinge was a clear indication of which room was considered internal. Nowadays, we assume that the swing of the door into one area indicates the direction of entry.
In the Absence of a Clear Indication
If both rooms are accessible from the front door, equally trafficked, equally used, and there is no indication from the hinge (e.g. the doorway leading between them has no door), both doorposts can be considered right doorposts of an entrance, and one can place the mezuzah on either one.
 Yoma 12b.
 Rema Y.D. 289:2; Shach 289:5.
 Shulchan Aruch Y.D. 289:2.
 Beit Yosef Y.D. 289; Bei’ur HaGra Y.D. 289:9.
 Chayei Adam 15:8; Kitzur Shulchan Aruch 11:4. Cf. Agur B’ohalecha 27:14, who opines that most authorities hold that the indication from the hinge takes precedent over the main room factor.
 Priority 4.
 Priority 3.
 This is determined by the first entry through the doorway and not be the subsequent re-entry into the original room.
 Da’as Kedoshim 289:11; Igros Moshe Y.D. 1:176; Chovas HaDar 8:4; Agur B’ohalecha 27:13. The language of Kitzur Shulchan Aruch here is ambiguous regarding the criteria of “main entrance.”
 Chayei Adam 15:18; Agur B’ohalecha 27:25; Sha’arei HaMezuzah 13:17. Cf. Da’as Kedoshim 289:12, who asserts that one considers the qualitative importance of the activities, e.g. sleeping vs. eating.
 Priority One.
 Priority Two.
 Chayei Adam 15:18; Agur B’ohalecha 27:25.
 Shevet HaLevi 2:152; Agur B’ohalecha 27:36. One should not recite a berachah on this placement. Cf. Igros Moshe Y.D. 1:176, who exempts this doorway completely.