However, two boards placed on the sukka do not combine. Rabbi Meir says: Even boards are like sheets, in that they join together to constitute the measure of unfitness.

The Gemara elaborates: Granted, according to Shmuel, who said that the dispute between Rabbi Yehuda and Rabbi Meir is with regard to boards that do not have four handbreadths in their width, but if they have four handbreadths in their width everyone agrees that it is unfit; what is the meaning of that which Rabbi Meir said: Boards join together? It means that boards less than four handbreadths wide combine to measure four handbreadths, which renders the sukka unfit.

However, according to Rav, who said that the dispute is with regard to boards that have four handbreadths in their width, but if they do not have four handbreadths in their width everyone agrees that it is fit, what are the circumstances? If each of the boards has four handbreadths in its width, why must they join together to render the sukka unfit? If each board is four handbreadths wide, each is capable of rendering the sukka unfit on its own. And if each of the boards does not have four handbreadths in its width, why would Rabbi Meir prohibit their use? But aren’t they merely reeds according to Rav? Just as one may roof the sukka with reeds, one should be permitted to roof the sukka with these narrow boards.

The Gemara answers: Actually, explain that there are four handbreadths in the width of each board and each renders the sukka unfit on its own. However, what is the meaning of: Boards join together? It is with regard to a completely different matter. They join together to constitute four cubits from the side. If one placed these unfit boards adjacent to one of the walls of the sukka, they do not render the sukka unfit, due to the halakhic principle of curved wall, which views that roofing as an extension of that wall. However, that principle applies only up to four cubits of unfit roofing. If these boards join together to measure four cubits, the sukka is unfit according to Rabbi Meir. According to this explanation, the mishna can be explained in accordance with the opinion of Rav as well.

There is another version of the above exchange. Granted, according to Shmuel, who said that the dispute between Rabbi Yehuda and Rabbi Meir is with regard to boards that do not have four handbreadths in their width, but if they have four handbreadths in their width, everyone agrees that it is unfit, what is the meaning of that which Rabbi Meir said: Boards join together? It means that they join together to constitute four cubits from the side, which renders the sukka unfit.

However, according to Rav, granted, according to Rabbi Meir, what is the meaning of: Boards join together? It means that they join together to constitute four cubits from the side. However, according to the opinion of Rabbi Yehuda, who said that even if they have four handbreadths in their width, the sukka is fit, what is the meaning of: Boards do not join together? They are merely reeds, which is fit roofing and fit roofing that joins together remains fit roofing. The Gemara answers: Since Rabbi Meir used the phrase: Join together, Rabbi Yehuda, although it is irrelevant according to his opinion, also said: Do not join together.

The Gemara notes: It is taught in a baraita in accordance with the opinion of Rav, and it is taught in a baraita in accordance with the opinion of Shmuel.

It is taught in a baraita in accordance with the opinion of Rav: If one roofed the sukka with cedar boards that do not have four handbreadths in their width, everyone agrees that it is fit. If there are four handbreadths in their width, Rabbi Meir deems it unfit and Rabbi Yehuda deems it fit.

Rabbi Yehuda said: There was an incident during a time of danger, when the gentiles decreed that it is prohibited for Jews to construct a sukka, at which point we brought boards that had four handbreadths in their width, and we roofed the porch with them so that it would not appear to be a sukka, and we sat beneath them. Evidently, boards four handbreadths wide are fit roofing for a sukka. They said to him: Is there proof to be cited from there? There is no proof from actions performed during a time of danger. It is possible that the sukka that they built on the porch was unfit, and they built it merely to commemorate the mitzva that they were unable to fulfill. From this baraita, it is apparent that the dispute between Rabbi Meir and Rabbi Yehuda is in a case of boards that are four handbreadths wide, in accordance with the opinion of Rav.

It is taught in a baraita in accordance with the opinion of Shmuel: If one roofed the sukka with cedar boards that have four handbreadths in their width, everyone agrees that the sukka is unfit. If there are not four handbreadths in their width, Rabbi Meir deems it unfit and Rabbi Yehuda deems it fit. And Rabbi Meir concedes that, if there is between one board and another board a gap the complete width of a board, then one places fit roofing from the waste of the threshing floor and the winepress, and the sukka is fit. And Rabbi Yehuda concedes that if one roofed the sukka with a board that is four handbreadths wide adjacent to one of the walls, the sukka is fit based on the principle of curved wall; and, nevertheless, one may not sleep beneath that board, and one who sleeps beneath it does not fulfill his obligation. In any event, there are two baraitot, each in accordance with one of the two views presented.

§ It is stated that there is an amoraic dispute: If one turned the unfit boards on their sides, and the width of the side is less than the measure that renders them unfit, do the boards remain unfit, or are they fit because in their current placement their width is narrower? Rav Huna said: The sukka is unfit, and Rav Ḥisda and Rabba bar Rav Huna said: It is fit.

The Gemara relates: Rav Naḥman happened to come to Sura. Rav Ḥisda and Rabba bar Rav Huna entered before him. They said to him: If one turned these boards on their sides and roofed the sukka, what is the halakha? They sought to ascertain whether his ruling is in accordance with their opinion or in accordance with the opinion of Rav Huna. He said to them: The sukka is unfit; since the boards are unfit roofing when placed flat, their legal status became like that of skewers [shapudin] of metal, which are unfit under all circumstances.

When they related this encounter to Rav Huna, Rav Huna said to them: Didn’t I tell you that you should say the halakha in accordance with my opinion? Even Rav Naḥman agrees with me. They said to him: And did the Master actually say a reason for this ruling to us, and we did not accept it from him? Rav Naḥman not only issued a ruling, he also explained his ruling to us. He said to them: And did you ask me for the reason and I did not say it to you?

The Gemara notes: Let us say that this baraita supports the opinion of Rav Huna: With regard to a sukka that does not hold one’s head, most of his body, and his table; a sukka whose wall was breached with a breach large enough for a goat to jump through headlong, i.e., three handbreadths; a sukka that one placed atop it a board that is four handbreadths wide, even if he only introduced three handbreadths of the board into the sukka, in all these cases, the sukka is unfit.

What are the circumstances of the case where one introduces only three handbreadths of a board that is four handbreadths wide? What, is it not that he turned the board on its side, thereby diminishing its width from four to three handbreadths, in accordance with the opinion of Rav Huna? The Gemara rejects this: No, with what are we dealing here? It is a case where one placed the board over the entrance of the sukka, where there is no wall. He introduced three handbreadths into the sukka and took one handbreadth out of the sukka, so that the legal status of that part of the board would be like that of roofing that protrudes from the sukka, and the halakha is that the legal status of any roofing that protrudes from the sukka is considered like that of the sukka. However, since this board is not adjacent to the wall of a sukka, the principle of curved wall does not apply. Therefore, it is four handbreadths of unfit roofing; it is prohibited to sleep beneath that board, and the entire sukka is rendered unfit. Consequently, there is no support for or against the opinion of Rav Huna from this baraita.