Translation:Mishnah/Seder Moed/Tractate Eruvin/Chapter 1/1

Introduction
Normally, on Shabbat, one is not allowed to transfer an item between one domain and another. (For example, one's house is a private domain, while a public street is a public domain. A more complete explanation is unfortunately beyond the scope of this mishnah). Biblically, one is allowed to transfer from a private domain to karmelit, a semi-private domain such as a dead-end alleyway which leads only to a residence or two. The rabbis however forbid transfering an object between two such domains unless there is an eruv (or, more specifically, an eruv chatzerot) present.

In the case of an alleyway, one of the methods of constructing an eruv is by creating a cross beam accross the top of the opening of the allewyay. (Other methods of creating an eruv in an alleyway are discussed later). This mishnah begins by discussing the specifications of this cross-beam.

Hebrew Text

 * מבוי שהוא גבוה למעלה מעשרים אמה, ימעט.
 * רבי יהודה אומר, אינו צריך.
 * והרחב מעשר אמות, ימעט.
 * ואם יש לו צורת פתח,
 * אף על פי שהוא רחב מעשר אמות, אינו צריך למעט.

Explanation
Amot: One amma is about 45.72cm (SI) or 1.5 feet (US).

One must lower it: The sages hold the crossbeam must be lower than 20 amot from the ground, although Rabbi Yehudah disagrees with this opinion. Given the conversion of units, this is about 9.144m (SI) or 10 yards (US).

One must reduce: The width of the alleyway must be no more than 10 amot. This is about 4.572m (SI) or 5 yards (US).

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