Shiur summary (draft from the recording)
Schach over a tree; sukkah on top of sukkah
סוכה על גבי סוכה
Sukkah 10a · Monday, August 31, 2026
The sugya
The shiur finished the sugya of a sukkah under a tree: the Mishnah of the vine shows that schach pasul that was beaten down is not combined, and the chiddush is that this is allowed even l'chatchila. It then moved to the Mishnah of sukkah al gabei sukkah. It covered the Braisa learning from 'basukkos teishvu' that a sukkah under a sukkah, a tree or a house is pasul, the kasha of 'adaraba', and Rav Nachman bar Yitzchak's teirutz 'basukkas ksiv'. The shiur then began Rebbi Yirmiyah's four combinations and explained the first two: both kosher, and both pasul.
Step by step (shakla v’tarya)
- MishnahMishnah cited: if one trains a vine, a squash plant or ivy over the sukkah and puts kosher schach on top, it is pasul. If the kosher schach is more than them, or he cut them from the ground, it is kosher.
- GemaraWhat is the case? If the vines are not beaten down and mixed in, schach pasul combines with schach kosher and it should be pasul.
- Ra'ayahSo it must be where they are beaten down and mixed together. We see from here that we do not make a gezeirah because of a case where they were not beaten down.
- TeirutzThen what is the chiddush? Mahu d'teima: from that Mishnah alone I would have thought it is kosher only b'dieved, and a Rav asked l'chatchila would say no. Kamashma lan it is allowed even l'chatchila.
- MaskanaThe chiddush of our Mishnah is that you may do it l'chatchila.
- MishnahMishnah: sukkah al gabei sukkah.
- GemaraBraisa: 'basukkas teishvu' is written in the singular, which teaches that only one type of sukkah works. This excludes a sukkah under a sukkah, a sukkah under a tree, and a sukkah inside a house (under a roof).
- The RebbiThe Rebbi noted, as said earlier, that a tree and a roof are really the same mechanics.
- KashaAdaraba: 'basukkos', the way it is read, sounds like many (tarti mashma). Why focus on one reading over the other?
- TeirutzRav Nachman bar Yitzchak: 'basukkas ksiv'. Even if we hold yesh eim lamikra, there must be something learned from the way it is written. What we learn is that only one type of sukkah works: a good sukkah on its own.
- ChazarahThe Braisa was reviewed with punctuation: the pasuk in quotes, then three cases excluded, end of the Braisa. Then the Gemara's 'adaraba' as a question, and Rav Nachman bar Yitzchak's answer.
- The RebbiWhat is excluded is any sukkah that is not a sukkah on its own. A sukkah under a tree or in a house is not a sukkah on its own.
- Discussion: the derivation that counts how many times the word 'sukkah' is written does not define what a sukkah is. Here we learn from the word itself that only one sukkah works, and anything with an auxiliary over it (tree, house, another sukkah) is not a sukkah on its own.
- The RebbiIntro to Rebbi Yirmiyah: there are really a few moving pieces repeated over and over. (1) Schach over 20 amos that is not good (sparse) becomes schach pasul, attributed to Rashi; it is not just a bad sukkah. (2) A lower sukkah with a good sukkah on top of it is always pasul.
- GemaraRebbi Yirmiyah lists four combinations: both kosher; both pasul; lower kosher and upper pasul; lower pasul and upper kosher.
- GemaraCase 1, both kosher: the lower one's sun is more than its shade, the upper one's shade is more than its sun, and the upper one stands within 20.
- The RebbiThe lower schach is as if it does not exist; it is one tall sukkah. Without the upper one, the lower one would be pasul. The upper must be within 20 of the ground so its schach works for the bottom too.
- The RebbiIf the upper one were over 20 from the ground, it would be a sukkah on its own. Its schach could not work for the bottom one, and the bottom one would be pasul for lack of schach.
- ChazarahReview: it is a misnomer to call it two sukkahs. It is really one sukkah from the top, and the top schach works for the whole structure because it is under 20.
- GemaraCase 2, both pasul: both have shade more than sun, and the upper stands above 20 amos.
- The RebbiHere 'above 20' is measured from the upper sukkah's own floor, which is the lower sukkah's schach, not from the ground. In case 1 it was measured from the ground.
- The RebbiThe bottom one is a valid sukkah on its own. It is pasul only because valid schach above it makes it sukkah al gabei sukkah, even though that schach is over 20. The top one is pasul because it is over 20 from its floor.
- The Gemara will ask later what the chiddush is in each of these cases. For now we are only explaining how each is pasul or kosher.
- ChazarahSummary: in both kosher, the bottom is not really a sukkah, and the upper schach (under 20 from the ground) serves both. In both pasul, the bottom is pasul as sukkah al gabei sukkah and the top because it is too tall.
Kashas
- If the vines are not beaten down, schach pasul combines with schach kosher. How can the Mishnah call it kosher?
- If it is where they were beaten down, what is the chiddush?
- Adaraba: 'basukkos' as read sounds plural (tarti mashma).
Teirutzim
- It is where they were beaten down, and we do not make a gezeirah because of where they were not.
- I would have thought it is kosher only b'dieved. The chiddush is that it is allowed l'chatchila.
- Rav Nachman bar Yitzchak: 'basukkas ksiv'. Even with yesh eim lamikra, we learn from the ksiv that only one type of sukkah works.
Rashi & Tosafos
- Rashi: According to Rashi, schach over 20 amos that does not provide enough shade becomes schach pasul. It does not merely fail to make a good sukkah.
Mareh mekomos
- Mishnah of training a vine, squash or ivy over the sukkah: proof that beaten-down schach pasul is not combined, and we do not make a gezeirah.
- Pasuk 'basukkos teishvu', written 'basukkas': the Braisa's source excluding a sukkah under a sukkah, under a tree, or in a house.
The Rebbi’s chiddushim
- A tree and a roof are really the same mechanics.
- The singular 'basukkas' excludes anything that is not a sukkah on its own, such as one under a tree, a house or another sukkah.
- Rebbi Yirmiyah's cases are built from the same few moving pieces: over-20 sparse schach becoming schach pasul, and a lower sukkah under good schach always being pasul.
- In the both-kosher case it is really one sukkah, and the lower sparse schach is as if it does not exist.
- In the both-pasul case, 20 amos is measured from the upper sukkah's own floor (the lower schach). In the both-kosher case it is measured from the ground.
Unclear in recording
- Who is cited as explaining the Mishnah ('the Rav') is unclear in recording.
- Remark about a change in girsa ('the Gilean changes the girsot') is unclear in recording.
- A side question about learning that a sukkah cannot be permanent, and whether this comes from 'seven days', is unclear in recording.
- The third of the 'three pieces' was not clearly stated.
- A comment at this point ('dir as-sufa') is unclear in recording.
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.