How to turn a breach into an entrance TB Eiruvin 11

The Mishnah at the very beginning of this chapter, TB Eiruvin 2a, distinguishes an entrance and a breach in a wall. “If the entrance to the alleyway is wider than ten cubits, one must diminish its width. However, if the entrance to the alleyway has the form of a doorway, i.e., two vertical posts on the two sides, and a horizontal beam spanning the space between them, even if it is wider than ten cubits, he need not diminish it, as it is then regarded as an entrance, rather than a breach, even if it is very wide.” (Sefaria.org translation) The form of a doorway (צוּרַת הפֶּתַח) turns a breach into a doorway allowing a person to carry in the alleyway. (Shukkhan Arukh, Hilkhot Shabbat, 362:10)

 Up to now there’s been no practical halakha for us because our housing developments is different than those described in the Talmud. Back then at least two houses opened up into a walled courtyard and at least two courtyards opened up into a walled alleyway (מבוי). The alleyway opened up to the public domain. Even though the alleyway is technically a private domain, the rabbis demanded an adjustment of either a side post (לחי) or a crossbeam (קורה) to serve as a reminder that one is approaching the public domain in order to carry within the alleyway and no further.

We generally think of the wire encircling a city or any part of the city as the eiruv, but technically what we are creating are forms of a doorway. Today’s daf TB Eiruvin discusses some of the halakhic requirements. Because the Gemara compares symbolic walls of poles with vines attached to them concerning the laws of mixing diverse seeds and Shabbat, we can divine some practical halakha.

 The first requirement is that the vines or in our reality the wire connecting the two poles must be attached on top and not to the side of the pole when it comes to Shabbat. “Rav Ḥisda said: If one prepared an opening in the form of a doorway from the side, placing the horizontal cross beam to the sides, rather than on top, of the vertical posts, he has not done anything.” (Shukkhan Arukh, Hilkhot Shabbat, 362:11) The second requirement is that the wire must be strong enough to hold up the lightest of doors. “And Rav Ḥisda also said: The opening in the form of a doorway of which the Sages spoke must be strong enough to mount a door in it, and even if it is merely a flimsy door of straw.” (Shukkhan Arukh, Hilkhot Shabbat, 362:11) Although Rabbi Yannai said that the poles need sockets for a door could be mounted, this is deemed unnecessary. The third and most interesting aspect of this symbolic doorway is the fact that the wire doesn’t need to come in contact with the poles at all. “A Sage taught a baraita: The form of a doorway of which they spoke consists of a reed from here, on one side, and a reed from there, on the opposite side, and a reed on top of them. The Gemara asks: Need the lower reeds reach high enough to touch the upper reed, or do they not need to touch it? Rav Naḥman said: They do not need to touch it; and Rav Sheshet said: They need to touch it.” (All quotes are from Sefaria.org translation) the halakha follows Rav Naḥman. (Shukkhan Arukh, Hilkhot Shabbat, 362:11)

דבר אחר -In the course of the discussion, the Gemara tells a wonderful story which teaches us an important lesson.  “As Rabbi Yehoshua went to Rabbi Yoḥanan ben Nuri to study Torah, even though Rabbi Yehoshua himself was an expert in the halakhot of diverse kinds and found him sitting among the trees, and Rabbi Yehoshua stretched a vine from one tree to another and said to him: Rabbi, if there are grapevines here, in the enclosed area, what is the halakha with regard to sowing diverse kinds of seeds here, on the other side of the partition? Rabbi Yoḥanan ben Nuri said to him: In a case where the trees are only ten cubits apart, it is permitted; however, where they are more than ten cubits apart, it is prohibited.” (Sefaria.org translation) Even though Rabbi Yehoshua was an expert concerning the prohibition of planting diverse kinds of seeds together (כִּלְאַיִם), he wanted to learn more Torah and was not embarrassed to ask another person’s opinion. We all should be as eager as Rabbi Yehoshua to learn from other people and not let our own ego get in the way of asking questions. By the way the halakha concerning planting diverse seeds together doesn’t follow Rabbi Yoḥanan ben Nuri.