What are the circumstances? It is in a case where in the lower sukka, its shade is greater than its sunlight, rendering the sukka fit, and in the upper sukka, its sunlight is greater than its shade and it is therefore insignificant, and the roofing of both is within twenty cubits of the ground.

And there are times when the upper sukka is fit and the lower sukka is unfit. What are the circumstances? It is in a case where in both sukkot their shade is greater than their sunlight, and the roofing of the upper sukka is within twenty cubits of the roofing of the lower one. In this case the upper sukka is fit, while the lower sukka is a sukka beneath a sukka and is unfit.

The Gemara asks: This is obvious. There is nothing novel in any of these scenarios. The Gemara answers: It was necessary for the tanna to mention the case where the lower sukka is fit and the upper sukka is unfit, as it contains a novel element. Lest you say: Let us issue a decree and deem the lower sukka unfit, as perhaps the unfit roofing of the upper sukka joins together with the fit roofing of the lower sukka and renders it unfit as well; therefore, the tanna teaches us that the two roofings do not join together and the upper roofing does not render the lower sukka unfit.

The Gemara elucidates this halakha. How much space shall there be between the roofing of the upper sukka and the roofing of the lower sukka for the lower sukka to be considered a discrete entity and therefore disqualified as a sukka beneath a sukka?

Rav Huna said: There must be a handbreadth of space, as we likewise find in tents of ritual impurity the measure of a handbreadth. With regard to the halakhot of ritual impurity imparted by a corpse, the legal status of the space of one handbreadth beneath a roof is that of a tent, as we learned in a mishna: A space measuring one handbreadth by one handbreadth with a height of one handbreadth transmits ritual impurity. If a source of ritual impurity imparted by a corpse is in that space, the impurity is transmitted to all people, vessels, and food in that space. And a space that size serves as a barrier before the spread of ritual impurity beyond that space. However, if the space measures less than the height of one handbreadth, it does not transmit impurity to the objects in that space, and it does not serve as a barrier before the spread of ritual impurity. The impurity breaches the confining walls and rises upward as if there were no covering over it.

Rav Ḥisda and Rabba bar Rav Huna say: For this to be considered a sukka beneath a sukka, the space between the roofing of the upper sukka and that of the lower one must measure at least four handbreadths, as we do not find a significant area that measures less than four handbreadths, e.g., with regard to the domains of Shabbat.

And Shmuel said: The space between the roofing of the upper sukka and that of the lower one must measure at least ten handbreadths. The Gemara asks: What is the rationale for the opinion of Shmuel? The Gemara explains: As the criterion for its fitness, so too is the criterion for its unfitness; just as its fitness is only in a sukka ten handbreadths high, so too, its unfitness as a sukka is engendered only by a sukka ten handbreadths high.

The Gemara questions Shmuel’s statement: We learned in the mishna that Rabbi Yehuda says: If there are no residents in the upper sukka, the lower sukka is fit.

The Gemara clarifies: What is the meaning of: There are no residents? If we say that it means that there are no actual residents, the question arises: Is that to say that residents cause it to be unfit? If the upper sukka is a fit sukka, is there any difference whether or not people reside there? Rather, what is the meaning of: There are no residents? Is it not referring to any sukka that is not suitable to serve as a residence? And what are the circumstances of that case? It is a case where the sukka is not ten handbreadths high, as anything less than ten handbreadths high is not considered a residence. From the fact that it is Rabbi Yehuda who distinguishes between whether or not the upper sukka is at least ten handbreadths high, conclude by inference that the first tanna of the mishna holds that the lower sukka is unfit even if the upper sukka is less than ten handbreadths high and therefore not suitable to serve as a residence. This is contrary to the opinion of Shmuel.

When Rav Dimi came from Eretz Yisrael to Babylonia, he said that the Sages say in the West, Eretz Yisrael, in explanation of the mishna: If the roofing of the lower sukka is not sufficiently sturdy to be able to support the cushions and blankets of the upper sukka, then the lower sukka is fit, as the upper sukka is not suitable to serve as an independent residence. According to this explanation, the mishna does not discuss the height of the upper sukka; it discusses the quality of the roofing.

The Gemara notes: Is that to say by inference that the first tanna holds that even though the roofing of the lower sukka is not sufficiently sturdy to be able to support the cushions and blankets of the upper sukka, the lower sukka is unfit? In that case, the upper sukka is not a suitable residence. Why should the lower sukka be unfit?

The Gemara answers: The first tanna agrees that if the roofing of the lower sukka is unable to support the cushions and the blankets at all, the upper sukka is not considered a sukka and the lower sukka is fit. However, there is a practical difference between the opinions of the first tanna and Rabbi Yehuda in a case where the roofing of the lower sukka is able to support the cushions and the blankets of the upper sukka with difficulty and there is a concern that the roofing might collapse. In that case, the first tanna holds that since the roofing is capable of supporting the cushions and blankets, the upper sukka is considered a separate sukka and renders the lower sukka unfit. According to Rabbi Yehuda, since the roofing is able to support the weight of the cushions and blankets only with difficulty, the upper sukka is not fit. Therefore, the lower sukka is fit.

MISHNA: If one spread a sheet over the roofing as protection for those sitting in the sukka due to the sun, or if one spread a sheet beneath the roofing as protection due to the falling leaves, or if one spread a sheet as a canopy over the frame of a four-post [kinof] bed, the area in the sukka beneath the sheets is unfit. In the first two cases, because the sheet is susceptible to ritual impurity, it renders the otherwise fit roofing unfit. In the case of the canopy, one is not sitting under the roofing of the sukka; rather, he is sitting inside a tent. However, one may spread the sheet over the frame of a two-post [naklitei] bed, which has one post in the middle of each end of the bed. When spreading the sheet over the posts it forms an inclined rather than a flat roof, and a tent with an inclined roof is not considered a significant structure.

GEMARA: Rav Ḥisda said: The Sages taught the ruling that the sheet renders the sukka unfit only when it is placed underneath the roofing due to the falling leaves; however, if his intent was to spread the sheet for decorative purposes to beautify the sukka, it is not in the category of roofing and the sukka is fit. The Gemara asks: This is obvious, as: Due to the falling leaves, is what we learned in the mishna. The Gemara answers: Lest you say that the same is true, i.e., the sukka is unfit, even when the sheet was spread to beautify the sukka, and the reason that the mishna teaches specifically the case where one spread the sheet due to the falling leaves is that the mishna teaches the matter, spreading a sheet in the sukka, in the manner in which it typically occurs. Rav Ḥisda teaches us that the formulation of the mishna is precise and the halakha applies specifically to the case cited. If one spread the sheet for decorative purposes, it does not render the sukka unfit.

The Gemara suggests: Let us say that the following Tosefta supports the opinion of Rav Ḥisda. If one roofed the sukka in accordance with its halakhic requirements, and decorated it with colorful curtains and sheets, and hung in it ornamental nuts, almonds, peaches, and pomegranates, grape branches [parkilei], and wreaths of stalks of grain, wines, oils, and vessels full of flour, it is prohibited to derive benefit and use them