מקום שיש לו ג' מחיצות אסרו חכמים לטלטל בו עד שיעשה שום תיקון ברביעית:

**Laws of an Alleyway (Mavoi) and a Side-Post (Lechi) — 36 Sections A place that has three walls — the Sages forbade carrying within it until some corrective arrangement is made on the fourth side.

A courtyard that was breached across its full width up to ten cubits may be rectified with a post four handbreadths wide placed on one side at the breach. If one wishes to rectify it with posts on both sides of the breach, two posts of any minimal width suffice. The same applies if a fourth wall remains standing, measuring four handbreadths in one place, or if one handbreadth remains on each side. All of this must be at a height of ten handbreadths. Even if the breach is less than four handbreadths wide, since it spans the full width it still requires rectification until it is less than three handbreadths. If the breach exceeds ten cubits, even if it does not span the full width, it must be rectified with a doorframe shape (tzurat hapetach).

An alleyway that has three walls and is open on the fourth side may be permitted by a side-post (lechi) — meaning, as Targum translates, "one board" (lucha chada) — of any thickness and width, placed at the entrance of the alleyway, at least ten handbreadths high. It may be made of any material, even a living creature, provided it is tied there with ropes to the walls of the alleyway by pegs projecting from the walls, in such a way that it cannot lie down and thereby be reduced below ten handbreadths.Even if a person is tied there, it also constitutes a lechi.

4. If there is some wall on the fourth side, it counts as a lechi, provided it is at least one handbreadth wide.

5. A lechi that would be blown over by the wind does not count as a lechi.

6. The lechi must not be more than three handbreadths away from the wall.

7. Even broken pieces, and pieces of broken pieces, are valid for a lechi. Therefore, one may make a lechi from plaster spread on a wall, provided one takes care that it not be smeared away to less than three handbreadths from the ground.

8. A lechi made from the wood of an asherah (idolatrous tree) is valid.

9. Whether the projection of the lechi is visible to those standing inside the alleyway but not to those standing outside, or visible to those outside facing the alleyway opening but not to those inside — it is valid.

10. If it was placed three handbreadths from the wall, or raised three handbreadths from the ground, it is invalid. But if it was raised less than three handbreadths from the ground, even if it is only seven handbreadths and a hairsbreadth high, it is valid.

11. Even if it was not placed there as a lechi but happened to be there on its own, it is valid — provided one relied on it before Shabbat. But if one did not rely on it before Shabbat — for instance, there was another lechi and it fell on Shabbat and now one wishes to rely on this one — no. (But if there was no other lechi there before Shabbat, it is as if one had relied on it.)

12. A lechi that stands on its own — even if one relied on it before Shabbat — if the alleyway is wider than eight cubits and the lechi protrudes four cubits into it, it is not treated as a lechi and another lechi is needed; it should be placed on the opposite side. If one wishes to place it alongside the first, one should make it slightly thicker or thinner than the protrusion, so that it is recognizable as a lechi. But if it was explicitly placed as a lechi — which is publicly known that a lechi was made for this alleyway — even if it protrudes four cubits it is valid as a lechi.

13. A lechi drawn along the wall of the alleyway with its edge placed against the wall's thickness — flush on the inside but visible from the outside, such that the lechi's edge does not cover the full thickness of the wall — if the alleyway is less than four cubits wide it is treated as a lechi, and one may use the wall with its inner edge. If four cubits or more, it is treated as part of the alleyway and it is forbidden to use the entire alleyway since there is effectively no lechi.

14. There is another valid arrangement for an alleyway open on the fourth side: a beam (korah) placed on top of the alleyway. It must rest on the alleyway wall. But if two pegs were driven outside the alleyway — even right next to it — and the beam was placed on them, it is invalid.

15. The beam must be placed with the intent to permit the alleyway. But if it was not made for that purpose, even if one relied on it before Shabbat, it is invalid.

16. The beam we mentioned must have a minimum size. Therefore, if it was made from the wood of an asherah it is invalid, since it is destined for burning its measurement is considered nullified (ketutei mechtat shiureih).

17. The required width of the beam is one handbreadth, and its thickness may be any amount, provided it is strong enough to hold a half-brick (arich), which is three handbreadths. If it is four handbreadths wide, it need not be strong enough to hold a half-brick.

18. Regarding supports — if the beam rests on pegs projecting from the wall that are not a handbreadth wide nor three handbreadths long: some say the pegs must be strong enough to hold both the beam and a half-brick; others say they need only be strong enough to hold the beam alone.

19. If the beam is round, its circumference must be at least three handbreadths, which gives it a width of one handbreadth.

20. If the beam is curved and the curve bends outside the alleyway, or above twenty handbreadths, or below ten handbreadths: we consider whether, if the curvature were removed, the gap between the two ends would be less than three handbreadths — if so, it is valid; if not, invalid.

21. If the beam extends from one wall but does not reach the other — for instance, it rests on poles — or if there are two beams, one extending from one wall and one from the other, meeting in the middle: if the gap between them is less than three handbreadths, valid; if three handbreadths or more, invalid.

22. If two beams are placed side by side, neither wide enough alone to hold a half-brick, but together wide enough — i.e., totaling one handbreadth — and with less than three handbreadths between them, no additional beam is needed. If not, another beam must be brought. Some say they must be within one handbreadth of each other.

23. If one beam is higher and one is lower, we consider the upper one as if it were lower and the lower one as if it were higher — provided the upper one is not above twenty handbreadths, the lower not below ten, and there are not three handbreadths between them either vertically or horizontally when we consider them as having shifted to be side by side. Some rule this invalid.

24. If a mat was spread over the beam but does not reach the ground: if it is three handbreadths above the ground it is invalid, since the beam is covered and no longer visible as a beam, and it is not a partition either since it is three handbreadths off the ground. But if a wide beam was placed and extends a little below ten handbreadths, it is valid.

25. If two bent pegs were driven into the two walls of the alleyway, curving inward, and the beam was placed on them — and the pegs are not a handbreadth wide (which would make them count as a beam): if they are not three handbreadths higher than the walls and their bend does not extend three handbreadths, it is valid, since we consider them as if they were flush with the wall tops. If they are three handbreadths higher or their bend is three handbreadths, it is invalid.

26. The ruling that an alleyway is permitted by a lechi or beam applies only when its height is not less than ten full handbreadths, its width is no more than ten precise cubits, and its length is at least four full cubits. If any of these conditions is lacking, it can only be rectified with a doorframe shape. If the inner height exceeds twenty precise cubits, it cannot be rectified by a beam, but can be rectified by a lechi. If one wishes to rectify it with a beam, a decorative marking or design must be made on it — one marking on the wall in plaster or on the face of the beam — so that everyone looks at it. If the height exceeds twenty cubits and a structure is built beneath the beam to reduce it below twenty, a structure one handbreadth wide along the width of the beam suffices. But if the height is less than ten handbreadths and one carves into the ground to complete ten, one must carve four cubits into the alleyway across its full width. An alleyway is not permitted by a lechi or beam unless two courtyards open into it and each courtyard has two houses.(Even if all the courtyards open into each other.) Some disagree with this. Each entrance must be at least four handbreadths wide. There must be residents eating in each house, since the location of the bread determines the eruv. Even if one house belongs to a father and one to a son, and the son receives his meals from his father's table yet eats in his own house, they are considered as two. Even if one side has a non-Jew and one a Jew, this is sufficient. Furthermore, the length of the alleyway must exceed its width. If any of these conditions is lacking, it can only be rectified with a four-handbreadth post, two minimal posts on either side, or a doorframe shape.Some say the custom today is to rectify all alleyways with a doorframe shape, since all our alleyways have the status of courtyards. The widespread custom in these lands is to rectify them with a rope tied across the width of the alleyway. This rope does not have the status of a beam since it is not a handbreadth wide, but it works as a doorframe shape, which is valid even with reed at the top, as explained above at the end of Siman 362. Therefore one should be careful to place two poles ten handbreadths high directly beneath the rope, which then works even for a passage open on both ends (mavoi mefulash) as a doorframe shape, or even in a courtyard or wherever a doorframe shape works, as explained at the end of Siman 362.

27. A courtyard whose length exceeds its width has the status of an alleyway and may be permitted with a lechi or beam.Even if no courtyards and houses open into it, since it is not adjacent to a public domain but opens to an alleyway which opens to the public domain.

28. An alleyway less than three handbreadths wide requires no corrective arrangement at all, as it is considered sealed. Some say that any alleyway less than four handbreadths wide requires no arrangement.

29. An alleyway whose one side ends at the sea and whose other side ends at a public refuse heap requires nothing, since a public refuse heap is not expected to be cleared away, and we do not worry that the sea will deposit silt (shirton — a dry patch like an island from which the water receded and which becomes fit for planting). Some disagree and hold that we do worry that silt may rise and there would be no partition.

30. An alleyway with one long side and one short side — even if the long side does not exceed the short by four cubits — the beam is placed only opposite the short side. But if one wishes, a doorframe shape may be made diagonally, and the beam inside the alleyway may also be placed diagonally, so that one uses the short side opposite the short and the long side opposite the long.

31. If a lechi was placed in the middle of an alleyway, and there is a courtyard from the lechi outward, and those on the outside also placed a lechi at the head of the alleyway, they restrict one another and must make a joint eruv. If there is no courtyard, or there is a courtyard but the outsiders did not place a lechi at the alleyway head, those from the lechi inward are permitted and those outward are forbidden. But if two posts or a four-handbreadth post was placed in the middle — if the alleyway is no wider than ten cubits — or a doorframe shape was made — if wider than ten cubits — then even if there is a courtyard from the arrangement outward and the outsiders also made an arrangement at the alleyway head, each may make their own eruv and be permitted in their section.

32. Just as we ruled that a lechi may be placed in the middle of an alleyway, the same applies to placing a beam in the middle. All of this applies where the inner section has the proper status of an alleyway — its length not less than four cubits, its length exceeding its width, and houses and courtyards opening into it. If not, two minimal posts on either side, or one four-handbreadth post on one side, is required.

33. An alleyway twenty cubits wide may be rectified by placing a four-cubit-wide post in the middle, making each side of the post a separate alleyway — since the post's length is four cubits — and a beam is placed at the head of each. Care must be taken that the beam rests on the post or within three handbreadths of it. Each of the two alleyways created by the post must have houses and courtyards opening into it and satisfy all alleyway conditions. The area between the post and the middle wall of the alleyway has the status of a bent alleyway (mavoi akum), since these two alleyways curve and are open at both ends to a public domain. Some say it has the status of a bent alleyway only if the distance from the post to the middle wall exceeds ten cubits.

34. There is another way to rectify an alleyway twenty cubits wide: set back two cubits from the wall and place a three-cubit post, and do the same on the other side, leaving an opening of ten cubits. Alternatively, set back one cubit and place a post of one and a half cubits, then set back another cubit and place another post of one and a half cubits, doing the same on the other side. Or set back two cubits and two handbreadths and place a post of two cubits and four handbreadths, likewise on the other side. Similar arrangements work — provided the post is wider than the gap between it and the wall, for otherwise the air space on both sides would nullify it. Care must be taken not to leave a large opening while entering through a small one, for if this is done the alleyway's correction is nullified — unless a doorframe shape is made for the smaller opening.

35. The post used to reduce the alleyway's width need not be one solid post; reed by reed with gaps of less than three handbreadths suffices, since less than three handbreadths is treated as solid.

36. An alleyway that is level inside but slopes (midrón) down to the public domain, or is level with the public domain and slopes down inside — if the slope rises ten handbreadths within four cubits, it is treated as if it were entirely vertical and requires no corrective arrangement. (In this case, the mound counts as a partition.)