A bent alleyway (מבוי עקום) TB Eiruvin 6

Daf TB Eiruvin 6 continues the discussion of the necessary changes needed to allow carrying in a bent alleyway (מבוי עקום). Before the Gemara discusses the main topic of the daf, it asks the question whether a public domain can be fixed with an eiruv so that people may carry in it. Remember a public domain i.e. a street must be 16 amot wide, goes through the town where 600,000 inhabitants live. Basically there’s no way to adjust that public domain so that one may carry in it. Nevertheless, there is one example that permits carrying. That one example is Jerusalem. If the city, like Jerusalem back during Second Temple days, is surrounded by walls and on either side of the public road there are doors that locked at night, one may carry in it. 

“Rabbis said to him: One cannot render a public domain fit for carrying by means of an eiruv in this manner. Apparently, there is no way to establish an absolute public domain fit for carrying by means of an eiruv. The Gemara questions its previous conclusion: And if you say that it is only in this manner, by way of a side post or a cross beam, that a public domain cannot be rendered fit for carrying, but by means of doors it can be rendered fit for carrying. But this is not true, as didn’t Rabba bar Ḥana say that Rabbi Yoḥanan said: With regard to Jerusalem, were it not for the fact that its doors are locked at night, one would be liable for carrying in it on Shabbat, because its thoroughfares are regarded as a public domain? This shows that the presence of a door is not sufficient to render it permitted to carry in a public domain; rather, the door must actually be locked.” (Srfaria.org translation)

 We’ve been dealing with two different types of alleyways. The first is a closed alleyway (מבוי סתום) which only opens up on one side into the public domain. All person needs is a crossbeam (koreh- קורה) or a side post (lekhi- לחי) in order to carry in this kind of alleyway. The second kind of alleyway (מבוי מפולש) is one where both ends of the alleyway open into different two public domains. Picture two public domains running parallel to each other and this perpendicular open alleyway connects them. There is a disagreement what type of eiruv is needed to allow carrying in this מבוי מפולש.

“The Sages taught in a baraita: How does one render a public thoroughfare fit for carrying by means of an eiruv? He constructs an opening in the form of a doorway from here, on one side of the thoroughfare, and a side post or a cross beam from here, on the other side. Ḥananya disagrees and says: This is the subject of an early dispute between tanna’im, for Beit Shammai say: He constructs a door from here, on one side, and a door from here, on the other side, and when he exits and enters, he must lock the door. It is not sufficient to construct a symbolic door; rather, there must be a door that actually closes. And Beit Hillel say: He constructs a door from here, on one side, and a side post or a cross beam from here, on the other side.” (Srfaria.org translation)

The daf introduces a third kind of alleyway, a bent one (מבוי עקום). Now this alleyway can take one of two different shapes. It could be shaped like the letter “L” where this bent alleyway opens up to two different public domains. Or it could be shaped like the letter “U” where it opens up to the same public domain. Rav says they should be treated like a מבוי מפולש. Shmuel says it should be treated like a מבוי סתום.

“The Gemara describes a certain crooked, L-shaped alleyway that was in Neharde’a, upon which they imposed the stringency of Rav and the stringency of Shmuel, and required it to have doors. Therefore, they adopted the stringencies of both Rav and Shmuel: Rav’s stringency that an L-shaped alleyway is deemed an open alleyway, and Shmuel’s stringency that an open alleyway requires a door.” (Srfaria.org translation)