Rif Succah 2b {Succah 7a continues}

HIDE/SHOW IMAGE
2b

{Succah 7a continues}
That is to say -- a wall on this side and a wall on that side {parallel to it} and it is open {such that one can pass right through it} like an open alleyway -- it is valid; and that handbreadth, one places it whichever direction he wants.

Rabbi Simon cited Rabbi Yehoshua ben Levi: He should make a span {pas} of 4 and a bit handbreadths, and place it less than 3 handbreadths near a wall.

Why is it different there {where the walls are like an L } in that a single loose handbreadth suffices, and why is it different by a succah made like an alleyway {when the two walls are parallel | | } that we need a span of four and a bit handbreadths?

Over there {by the L}, there are two walls which combine {our gemara: which are as their law=normally; Rashi: which are made [avidan] as their law}, it is sufficient with a loose handbreadth. Here, where there are not two walls which combine, if there is a span of four and a bit handbreadths, yes, and if not, no.

Rava said: And it is not permitted {=made valid} except with a tzurat hapetach {appearance of a door}.
And some say:
Rava said: And it is also permitted with a tzurat hapetach.
And some say:
Rava said: And it also requires a tzurat hapetach.

To explain: If the succah had two walls - according to the phrasing that stated "and it is not permitted {=made valid} except with a tzurat hapetach" -- the handbreadth does not matter to us whether it exists or does not. And according to the phrasing that stated "and it is also permitted with a tzurat hapetach," it is permitted with one of them - either a tzurat hapetach or a loose handbreadth. And according to the phrasing that stated "and it also requires a tzurat hapetach," it is only permitted with both of them - with a tzurat hapetach and a loose handbreadth.

And the halacha is that it needs {both} a tzurat hapetach and a loose handbreadth, for we sat that Rav Ashi found that Rav Kahana made for himself a loose handbreadth in the middle and made a tzurat hapetach. He said to him: Does not Master hold like that which Rava said that "it is also permitted with a tzurat hapetach?" He said to him: I hold like the alternate phrasing which states "and it also requires a tzurat hapetach."