(Rav Yehudah): If a Mezuzah was written on two Dapim (Tosfos - parchments; Rashi - columns), it is Pasul.

Question (Beraisa): If a Mezuzah was written in two Dapim and one was put on each doorpost, it is Pasul.

Inference: If both were put on the same doorpost, it would be Kosher!

Answer: No, it means that if it was possible to (Rashi - cut between the columns and) put one Parshah on each doorpost, it is Pasul.

(Rav Yehudah): The Tzir determines where to put the Mezuzah.

Question: What is the Tzir?

Answer (Rav Ada): It is the holder of the door hinge.

Question: When does this apply?

Answer: It applies to a house divided into two, one side each for men and women, in order that the women will not encounter men (each has its own opening to Reshus ha'Rabim). There is a door between them. Whichever side the hinge is on is considered the primary house. The Mezuzah is put on the right side of one who enters it.

The Reish Galusa built a house. He asked Rav Nachman (his son-in-law) to affix the Mezuzah.

Version #1 -Tosfos - Rav Nachman: First attach the door (so I will know where to put the Mezuzah. The house was divided like above.)

Version #2 -Rashi - Rav Nachman: First attach the doorposts to the sides of the opening. (If a Mezuzah is attached to the doorpost and then the doorpost is attached to the opening, the Mezuzah is fixed in the opening 'by itself', the Mitzvah is not fulfilled.) (end of Version #2)

(Rav Yehudah): If a Mezuzah was attached like a bolt, it is Pasul.

Question: R. Yitzchak bar Yosef reported that all the Mezuzos in Rebbi's house were (Rosh - slanted; alternatively, bent) like bolts, and that there was no Mezuzah on Rebbi's opening (Tosfos - from his house) to the Beis Medrash.

Answer: If the Mezuzah rests like a horizontal bolt, it is Pasul (Rashi; R. Tam - Kosher);

If it is vertical (Rashi; alternatively, bent like the letter 'Nun'), it is Kosher (Rashi; R. Tam - Pasul).

Question: (R. Yitzchak said that that there was no Mezuzah on Rebbi's opening to the Beis Medrash). However, there was a Mezuzah on Rav Huna's opening to the Beis Medrash!

Answer: That is because he (Rashi - many people) normally went through that opening.

(Rav Yehudah): Normal usage determines the law regarding Mezuzah. (I.e. if a room has two openings, we put the Mezuzah on the opening used more often.)

(R. Zeira citing Shmuel): One should put the Mezuzah at the beginning of the top third of the doorway.

(Rav Huna): It must be at least one Tefach above the floor and at least one Tefach below the ceiling, anywhere in this range is Kosher.

Question (against R. Zeira - Beraisa - R. Yehudah): It must be at least one Tefach above the floor and at least one Tefach below the ceiling, anywhere in this range is Kosher;

R. Yosi says, "u'Kshartam (Tefilin)... u'Chsavtam (a Mezuzah)" - just like Tefilin are worn on the highest part (Rashi - of the head), Mezuzah is affixed on the upper part of the doorpost.

Rav Huna holds like R. Yehudah, but Shmuel is not like either Tana!

Answer (Rav Huna brei d'Rav Noson): Really, he holds like R. Yosi. Shmuel said 'at the beginning of the top third', i.e. one should not distance it from the top more than a third of the height of the doorway.

(Rava): The Mezuzah should be affixed in the Tefach closest to Reshus ha'Rabim.

Question: What is the reason?

Answer #1 (Rabanan): In this way, one encounters the Mitzvah as soon as possible, when entering the house.

Answer #2 (R. Chanina of Sura): In this way, the entire house (inside from the Mezuzah) is protected.

(R. Chanina): Hash-m's ways are unlike mortal's ways. A mortal king sits inside, and his servants guard him from the outside;

Hash-m's servants (Yisrael) are inside (their houses. They affix a Mezuzah), and He guards them from the outside - "Hash-m Shomrecha Hash-m Tzilcha Al Yad Yeminecha."

(Rav Yosef brei d'Rava): If the Mezuzah was put a Tefach into the wall, it is Pasul.

Support (Beraisa): If it was put in a doorpost, or if one covered it over with a doorframe:

If it is more than a Tefach from the opening, another Mezuzah must be affixed. If it is less than a Tefach, no other Mezuzah is needed.

Rejection: No. The Beraisa discusses Achorei ha'Deles (a minor opening to the side of the main opening; alternatively - on the other side of the corner). If the wall separating the Mezuzah from the other opening is less than a Tefach, the Mezuzah exempts the other opening as well.

Question: The Seifa explicitly teaches Achorei ha'Deles! (The Reisha must teach something else.)

Answer: The Seifa explains the Reisha.

(Beraisa): If a doorframe was made of reeds, he cuts a tube-shaped opening and inserts the Mezuzah in it.

(Rav Acha brei d'Rava): He must do it in this order. If he cut the hole, inserted the Mezuzah and then attached the frame to the door, it is Pasul. One must affix the Mezuzah to the doorpost, but not attach a doorpost with a Mezuzah to the opening.

(Rava): A desolate opening (this will be explained) is exempt from Mezuzah.

Question: What is a desolate opening?

Answer #1 (Rav Richumi or Aba Yosi): The opening does not have a (Tosfos - smooth) ceiling. (Alternatively - the room has no ceiling);

Answer #2 (The other of Rav Richumi and Aba Yosi): The opening does not have (Tosfos - smooth) doorposts. (Alternatively - it has no lintel);

(Rabah bar Shila): An Achsadra (a three-walled room, one side is open) is exempt from Mezuzah because it has no doorposts.

Question: This implies that if it has (beams like) doorposts, it requires a Mezuzah. However, they are not really doorposts. They are merely supports for the ceiling!

Answer: He means, an Achsadra is exempt even if it has doorposts, for they are merely supports for the ceiling.

(Abaye): I saw Rabah's Achsadra. It had doorposts, but no Mezuzah;

He holds that they are merely supports for the ceiling.

Question (Beraisa): A Beis Sha'ar (guard-house at the entrance to a Chatzer), Achsadra or porch must have a Mezuzah.

Answer #1: That refers to an Achsadra of Bei Rav. (It has four walls, but they do not reach to the ceiling.)

Objection: Achsadra of Bei Rav is a proper room! (There is no need to teach it.)

Answer #2: Rather, it refers to a Roman Achsadra (hut, the walls are full of openings. These are Rashi's definitions of Achsadra of Bei Rav and a Roman Achsadra. Bach switches these to conform to Rashi's Pirush on Bava Basra).

(Rachbah): Bei Harziki requires two Mezuzos.

Question: What is Bei Harziki?

Answer (Rav Papa Sava): It is a Beis Sha'ar open to a Chatzer, and houses are open to it.

(Beraisa - R. Yosi): If a Beis Sha'ar is open to a garden and Kitonis (a small room), it is like the Kitonis (this will be explained);

Chachamim say, it is like a Beis Sha'ar.

(Rav and Shmuel): All agree that the opening of the Beis Sha'ar to the Kitonis requires a Mezuzah. (Rashi prefers to say that this is if the hinges are on the side of the Kitonis.)

Question: What is the reason?

Answer: This is an entrance of the Kitonis!

The Tana'im argue about the opening of the Beis Sha'ar to the garden;

R. Yosi holds that this Beis Sha'ar is made primarily for the sake of (entering and leaving) the Kitonis, therefore all its openings are obligated (even if the hinges are on the side of the garden), like a regular Beis Sha'ar;

Chachamim hold that this Beis Sha'ar is made primarily for the sake of the garden, therefore, the openings between it and the garden are unimportant (and exempt).

(Rabah and Rav Yosef): All agree that the opening of the Beis Sha'ar to the garden is exempt.

Question: What is the reason?

Answer: This is an entrance of the garden.

The Tana'im argue about the opening of the Beis Sha'ar to the Kitonis:

R. Yosi holds that this is like an entrance of the Kitonis, therefore it is obligated;

Chachamim hold that the Beis Sha'ar is made primarily for the garden, therefore it is exempt.