POINT BY POINT SUMMARY
by Rabbi Ephraim Becker
Kollel Iyun Hadaf, Yerushalayim
Rosh Kollel: Rabbi Mordecai Kornfeld
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Previous dafSukah 17
SUKAH 17 - Dedicated by Seth and Sheila Jutan of Atlanta, Georgia, in memory
of her grandfather, Mr. Bernie Slotin (Dov Ber ben Moshe Mordechai z'l), who
passed away on Chol ha'Moed Pesach (18 Nisan 5759 - April 4, 1999).
1) MISHNAH: DOFEN AKUMAH
(a) An open space of three Tefachim between the wall and the
S'chach invalidates the S'chach.
2) DETAILS OF DOFEN AKUMAH
(b) A skylight in a room is invalid if it four Amos away from the
(c) A courtyard (three adjoining homes with a covered porch in
front of each) will be invalid if the ceiling of the porch is
(d) Similarly invalid is S'chach which is surrounded with four
Amos of invalid S'chach.
(a) Question: Why did we need three illustrations of Dofen Akumah?
(b) Answer: Each case has a potential leniency which might cause
us to limit the application of Dofen Akumah.
1. The case of the skylight might be lenient in that the
walls were constructed to enclose a dwelling (unlike the
walls of the homes in the courtyard which were not made
to enclose a dwelling).
(c) (Rabah, reporting the view of Rabanan d'vei Rav) A three-
Tefach break in the S'chach will invalidate the Sukah and four
Tefachim of S'chach Pasul will interrupt the Sukah.
2. The Sukah with S'chach Pasul around the side might be
lenient since those surrounding materials are fit for
S'chach (their Pesul is owing to Ta'aseh ve'Lo min
3. We thus are taught that Dofen Akumah applies in all
cases, even if the material of which the wall was made is
not fit to be used as S'chach at all.
(d) Question (Rabah): But our Mishnah allows S'chach Pasul up to
four Amos (while three Tefachim is only an open space)!?
(e) Answer (the Rabanan citing Rav and Shmuel): The Mishnah speaks
of the distance to the *side* of the Sukah (Dofen Akumah).
(f) Question (Rabah): But what of the case of a Sukah with less
than four Tefachim of S'chach Pasul next to less than three
Tefachim of space.
1. Surely it should be Kosher.
(g) Answer (Rabanan): With that reasoning, you (Rabah) should ask
yourself the same question (since according to you too, the
Shiur of air is even more stringent vis-a-vis S'chach Pasul
than it is according to us)!
2. If filling in that space with S'chach Pasul (which is
more lenient than space, since the Shiur of S'chach Pasul
is four Tefachim, while that of space is three) will
invalidate the Sukah, then why should the *space* (which
is stricter than S'chach Pasul) not likewise invalidate
(h) Question (Rabah): According to my opinion, four Amos is the
fixed Shiur of S'chach Pasul that disqualifies a Sukah while
the Shiur of space (three Tefachim) is unrelated to the Shiur
of S'chach Pasul and they do not combine to disqualify the
3) COMBINING DISTINCT SHIURIM (as learned in Sura)
1. According to you, however, in whose opinion the four
Tefachim of S'chach Pasul in the middle of the Sukah is
not a given Shiur, but a Sevara (based on four Tefachim
as a Makom Chashuv, ie. there is a significant area of
four Tefachim without Kosher S'chach) then what is the
difference if those four Tefachim are S'chach Pasul or
(i) Answer (Abaye): The case of a minimum Sukah, where the Shiurim
are the same (since three Tefachim of either space or of
S'chach Pasul will invalidate the Sukah) then space and
S'chach Pasul should combine even by a larger Sukah?
2. Hence Rabah's original question returns, if S'chach Pasul
invalidates the Sukah, the certainly space should?
(j) Question (Rabah): The invalidation of a minimum Sukah is not
the result of the Shiur of S'chach Pasul or of space, but
because there is lacking a Shiur Sukah!
(a) Question: Rabah's premise, that when Shiurim are distinct
(such as four Amos for S'chach Pasul and three Tefachim for
space) they do not combine, seems counter to the Mishnah in
4) COMBINING DISTINCT SHIURIM (as learned in Neharda'a)
1. The Shiur Tumah for cloth is three by three Tefachim; for
sackcloth, four by four; for leather, five by five; and
for reed mat, six by six.
(b) Answer: They combine to become Tameh because sometimes they
all have the same Shiur; whereas S'chach Pasul and space never
have the same Shiur.
2. Each of these will combine with the next in line (if sewn
together) to become subject to the more lenient Shiur of
Tumah (e.g. cloth with sackcloth combine to be subject to
a Shiur of four Tefachim; sackcloth with leather combine
to a Shiur of five; and leather and platted reeds to a
Shiur of six Tefachim.
1. All of the above materials have the same Shiur (of one
Tefach) when they are sewn as a patch into the
saddle-cloth of a donkey.
2. Question: Of what use is a cloth of one Tefach!?
3. Answer (Resh Lakish citing R. Yanai): It can serve as a
patch on the donkey.
(a) (R. Yehudah citing Shmuel) S'chach Pasul invalidates beyond
four Amos, when its area four by four Tefachim.
(b) (Rav) The Pesul of S'chach Pasul is always four Amos (the
position of Rabah in the Sura version).
(c) Question: What of the Mishnah, which allows a plank of four
1. This is understandable according to Rav, since S'chach
Pasul always invalidates with four Amos.
(d) Answer: That plank was at the side of the Sukah, within four
Amos of the wall.
2. But for Shmuel, this should be S'chach Pasul!?
(e) Question (on Rav): What of the first version of the Beraisa
discussed on 14a (that the Shiur for planks is four Tefachim)?
1. R. Meir holds that two planks combine (like cloths).
(f) Answer (Rav): The Beraisa speaks by planks of four Tefachim,
that are placed at the side of the Sukah which will invalidate
it if they total four Amos.
2. According to the first Lashon there, Rav holds that in
the middle of the Sukah, four *Tefachim* invalidate the
Sukah, then of what case is the Beraisa speaking?
i. If each plank is *four* Tefachim wide, then why
should it be necessary to combine two planks?
ii. If they are *less* than four Tefachim then for Rav
(who establishes the Machlokes between R. Meir and
R. Yehudah in the Mishnah on 14a by planks of four
Tefachim) anything *less than four* Tefachim is
S'chach Kosher, no matter how many combine to form