בטפח הסמוך לרשות הרבים כמה דמרחק מעלי קמ"ל in the handbreadth adjacent to the public domain, perhaps the further the mezuza is from the inside of the house the better, and one may affix it even fully outside the airspace of the entrance. To counter this, Shmuel teaches us that the mezuza must be within the airspace of the entrance itself.
ואמר רב יהודה אמר שמואל כתבה על שני דפין פסולה מיתיבי כתבה על שני דפין והניחה בשני סיפין פסולה הא בסף אחד כשרה ראויה לשני סיפין קאמר And Rav Yehuda says that Shmuel says: If one wrote a mezuza on two sheets it is unfit. The Gemara raises an objection from a baraita that teaches: If one wrote a mezuza on two sheets and placed it on the two doorposts of the entrance, it is unfit. The Gemara states the objection: By inference, if the mezuza was affixed on one doorpost, it is fit, despite the fact that it is written on two sheets. The Gemara answers: The baraita is not referring to a case where one affixed the mezuza on two doorposts. Rather, the baraita is saying that if it was written on two sheets in such a manner that it is fit to be affixed to two doorposts, i.e., there is a space between the writing of the first and second passages, so that one can separate the two sheets for different doorposts, it is unfit. This is in accordance with the statement of Rav Yehuda, citing Shmuel.
ואמר רב יהודה אמר שמואל במזוזה הלך אחר היכר ציר מאי היכר ציר אמר רב אדא אבקתא היכי דמי כגון פיתחא דבין תרי בתי בין בי גברי לבי נשי And Rav Yehuda says that Shmuel says: The halakha is that a mezuza must be affixed to the doorpost on its right side, and the right side is determined by the direction from which one enters the room. With regard to a mezuza, when deciding which side is the right side, one should follow the indication of the hinge. The The Gemara asks: What is the indication of the hinge? Rav Adda said: The socket into which the hinge is inserted. The room with the socket is considered the inside room, and the mezuza is affixed to the side which is on one’s right when entering that room. The Gemara asks: What are the circumstances, i.e., in what kind of case was this guideline to follow the indication of the hinge necessary? The Gemara answers: This indication is necessary in a case where there is an entrance that is between two houses, e.g., between a room for men and a room for women, as in such a situation the direction of the entrance is unclear.
ריש גלותא בנא ביתא אמר ליה לרב נחמן קבע לי מזוזתא א"ר נחמן תלי דשי ברישא The Gemara relates: The Exilarch built a new house. He said to Rav Naḥman: Affix mezuzot for me in the house. Rav Naḥman said: First erect the doors, so that I can affix the mezuzot in the appropriate places, according to the placement of the hinges.
אמר רב יהודה אמר רב עשאה כמין נגר פסולה איני והא כי אתא רב יצחק בר יוסף אמר כולהו מזוזתא דבי רבי כמין נגר הוו עבידן וההיא פיתחא דעייל ביה רבי לבי מדרשא לא הוה לה מזוזה לא קשיא הא דעבידא כסיכתא הא דעבידא כאיסתוירא Rav Yehuda says that Rav says: If one fashioned a mezuza like a bolt, i.e., he wedged it into a hole in the doorpost of a gate, or affixed it to the doorpost horizontally, it is unfit. The Gemara raises a difficulty: Is that so? But when Rav Yitzḥak bar Yosef came from Eretz Yisrael to Babylonia, he said: All the mezuzot in the house of Rabbi Yehuda HaNasi were fashioned like a bolt, and he also said: That entrance by which Rabbi Yehuda HaNasi entered the study hall did not have a mezuza. The Gemara answers: This is not difficult. This ruling, that it is unfit, is referring to a case where it is prepared like a peg, i.e., he inserted it deep into the doorpost while it was lying horizontally. That ruling, that it is fit, is referring to a case where it is prepared like an ankle [ke’istevira], i.e., it is vertical.
איני והא ההוא פיתחא דהוה עייל בה רב הונא לבי מדרשא והויא לה מזוזה ההוא רגיל הוה דאמר רב יהודה אמר רב במזוזה הלך אחר הרגיל With regard to the second element of Rav Yitzḥak bar Yosef’s statement, that the entrance by which Rabbi Yehuda HaNasi entered the study hall did not have a mezuza, the Gemara asks: Is that so? But what of that entrance by which Rav Huna would enter the study hall, which had a mezuza? The Gemara answers: That entrance was the one through which all were accustomed to enter the study hall. By contrast, the entrance that Rabbi Yehuda HaNasi used was a side entrance, which was designated for him alone. Consequently, it was exempt from the obligation to affix a mezuza, as Rav Yehuda says that Rav says: With regard to a mezuza, follow the entrance that people are accustomed to using.
א"ר זירא אמר רב מתנא אמר שמואל מצוה להניחה בתחלת שליש העליון ורב הונא אמר מגביה מן הקרקע טפח ומרחיק מן הקורה טפח וכל הפתח כולו כשר למזוזה § Rabbi Zeira says that Rav Mattana says that Shmuel says: It is a mitzva to place the mezuza at the beginning of the upper third of the doorpost. And Rav Huna says: One raises the mezuza a handbreadth from the ground, or one distances it from the cross beam, i.e., the lintel, a handbreadth, and the entire entrance between those two handbreadths is fit for the placement of the mezuza.
מיתיבי מגביה מן הקרקע טפח ומרחיק מן הקורה טפח וכל הפתח כולו כשר למזוזה דברי רבי יהודה רבי יוסי אומר וקשרתם וכתבתם מה קשירה בגובה אף כתיבה בגובה The Gemara raises an objection from a baraita: One raises the mezuza a handbreadth from the ground, or one distances it from the cross beam a handbreadth, and the entire entrance between those two handbreadths is fit for the placement of the mezuza; this is the statement of Rabbi Yehuda. Rabbi Yosei says: The verse states: “And you shall bind them for a sign upon your arm” (Deuteronomy 6:8), and then it states: “And you shall write them upon the doorposts of your house” (Deuteronomy 6:9). Just as the binding of the phylacteries is performed on the upper part of the arm, so too, the writing, i.e., the placement, of a mezuza must be specifically on the upper part of the entrance.
בשלמא לרב הונא הוא דאמר כר' יהודה אלא לשמואל דאמר כמאן לא כר' יהודה ולא כר' יוסי The Gemara explains the objection: Granted, according to Rav Huna, he states his ruling in accordance with the opinion of Rabbi Yehuda; but according to Shmuel, in accordance with whose opinion does he state his ruling? It is not in accordance with the opinion of Rabbi Yehuda, and it is not in accordance with the opinion of Rabbi Yosei.
אמר ר"ה בריה דרב נתן לעולם כרבי יוסי Rav Huna, son of Rav Natan, said: Actually, Shmuel’s ruling is in accordance with the opinion of Rabbi Yosei,