Shiur summary (draft from the recording)
Sukkah on Top of a Sukkah: Four Cases
סוכה על גבי סוכה
Sukkah 10a · from line 23 · Tuesday, September 1, 2026
The sugya
The shiur learned the Gemara on the Mishnah of a sukkah on top of a sukkah. The source is the pasuk "b'sukkos teshvu," read through the ksiv "b'sukkas." Then came R' Yirmiyah's four cases (both kosher, both pasul, lower kosher and upper pasul, lower pasul and upper kosher), worked through on a chart. For each case the chart records chamaso/tzilaso merubah for each level, the height of the upper level, and the reason. The shiur ended on the Gemara's "peshita," tentatively placed on the third case and left to be worked out.
Step by step (shakla v’tarya)
- GemaraTanu Rabbanan (line 24): "b'sukkos teshvu." Not in a sukkah under a sukkah, not in a sukkah under a tree, and not in a sukkah inside a house. The pasuk excludes these three.
- KashaLine 26: adarabba, the kri "b'sukkos" implies two (plural). So one should be allowed to sit in a sukkah under a sukkah.
- TeirutzRav Nachman bar Yitzchak: "b'sukkas" kesiv. It is written without the second vav, i.e. singular.
- The RebbiThere is a debate whether to follow the kri or the ksiv, but everyone agrees you must reckon with the ksiv. Here the ksiv is telling you something.
- This is the source for the Mishnah's rule that you cannot sit in a sukkah under a tree or under a sukkah. It serves as the intro to the next part of the sugya.
- ShitahR' Yirmiyah, who in Shas typically breaks cases down, lists four cases: both kosher; both pasul; lower kosher and upper pasul; lower pasul and upper kosher. The last is the case of our Mishnah.
- The chart columns are: - lower schach: chamaso or tzilaso merubah; - upper schach: chamaso or tzilaso merubah; - upper height: within or above 20 (is it 20 from the ground or from the roof of the lower one?); - the reason.
- GemaraCase 1, both kosher (lines 32-33): the lower is chamaso merubah mitzilaso, the upper is tzilaso merubah mechamaso, and the upper stands within 20 from the ground.
- The RebbiReason for case 1: the upper schach covers everything, so it is really one big two-decker sukkah. The lower layer is like a platform inside the sukkah and is not a hefsek.
- GemaraCase 2, both pasul (lines 35-36): both are tzilasan merubah mechamasan, and the upper stands above 20 amos.
- The RebbiReason for case 2: - The upper is pasul because it is above 20 (from the roof of the lower). - The lower is pasul because it sits under pasul schach, like being under a tree. - The upper schach is pasul for both sukkahs.
- GemaraCase 3, lower kosher and upper pasul (line 38): the lower is tzilaso merubah mechamaso, the upper is chamaso merubah mitzilaso, and both stand within 20.
- The RebbiReason for case 3: the lower has valid schach. The upper does not have enough schach for its own sukkah and is insignificant; it does not get in the way of the lower one.
- GemaraCase 4, lower pasul and upper kosher, the case of our Mishnah: both are tzilasan merubah, and the upper is within 20 from the roof of the lower. The lower is pasul because it is a sukkah under a sukkah.
- KashaWhy is the upper height measured from the ground in case 1 but from the roof of the lower sukkah in case 4?
- TeirutzIn case 1 the lower is not a real sukkah on its own and needs the top to make it kosher, so the height is measured from the ground. In case 4 the lower is a separate entity with its own schach, so its roof becomes a new 'ground' and the 20 is measured from there.
- GemaraThe Gemara asks on all this: "peshita."
- The Rebbi tentatively ('maybe') says the peshita is on the third case. The question was left to be worked out next time.
Kashas
- Adarabba: the kri "b'sukkos" is plural, implying a sukkah under a sukkah is allowed.
- Why is the upper height measured from the ground in case 1 but from the roof of the lower sukkah in case 4?
- The Gemara's "peshita" on R' Yirmiyah's cases, possibly on the third case.
Teirutzim
- Rav Nachman bar Yitzchak: "b'sukkas" kesiv, written without the vav, i.e. singular.
- In case 1 the lower is not a real sukkah on its own, so it is one sukkah measured from the ground. In case 4 the lower is a separate entity, so its roof is the new ground for measuring 20.
Rashi & Tosafos
- Rashi: The chart's entry that in case 4 the upper is within 20 from the roof of the lower sukkah is said to come from Rashi.
Mareh mekomos
- Pasuk in Vayikra, "b'sukkos teshvu": source for excluding a sukkah under a sukkah, under a tree and inside a house.
- The famous Gemara in Eilu Metziyos (kav b'arba amos, half a kav in two amos, etc.): an example of R' Yirmiyah breaking cases down.
The Rebbi’s chiddushim
- Even though there is a debate over following kri or ksiv, everyone agrees you must reckon with the ksiv. Here it teaches the halacha.
- R' Yirmiyah is not adding new rules. He applies rules already known in Sukkah to every combination.
- Case 1 is really one big two-decker sukkah. The lower layer is like a platform, not a hefsek, and someone under a bed placed on top is still in the sukkah.
- In case 2 the upper schach is pasul for both sukkahs. The lower is like a sukkah under a tree.
- In case 3 the upper schach is insignificant: below the line of 20 but not enough for its own sukkah, and it does not interfere with the lower one.
- There is no halachic revolution in these cases, which is why the Gemara will ask "peshita."
Unclear in recording
- The exact spelling correction (bracketing the second vav, line 24) and the reference to the gilyon are unclear in recording.
- Discussion of whether metal rods or wood in the lower layer would make a difference is unclear in recording.
- Case 2: the exchange about a sukkah under a tree that is chamaso vs. tzilaso merubah is unclear in recording.
- Case 3: the question about both levels being chamaso merubah within 20 and combining is unclear in recording.
- In the opening list, the labels for the third and fourth cases are garbled. They follow the order of the Gemara text.
Drafted from the recording of the shiur, for chazarah. Torah terms follow the Rebbi’s own words; anything that could not be made out is marked “unclear in recording”. Tap a time to hear that point. Corrections welcome.