GEMARA

Mishnah: If one spread a sheet over (the Sechach) to protect from the sun, or underneath to protect from things dropping (from the Sechach), or over (four) bedposts, (underneath the sheet) it is Pasul.

Rav Chisda: It is Pasul only if the intent was to protect from droppings. If he spread it for decoration, it is Kosher.

Support (Beraisa): If a Sukah with Sechach was adorned with any of the following, one may not use (or eat) them until after Simchas Torah:

Colorful, illustrated curtains and sheets, nuts, peaches, almonds, pomegranates, twigs with grapes clusters, crowns on ears (of grain), wines, oils and flour.

If he stipulated (that he may use them during Bein ha'Shemashos of the first night), it works (they do not become forbidden. The Beraisa connotes that there is no problem to be under them!)

Rejection: Perhaps the Beraisa discusses decorations on the side.

Rav Nachman: (Even) if Noyei Sukah are four Tefachim below the Sechach, it is Kosher;

Rav Chisda and Rabah bar Rav Huna: It is Pasul.

Rav Chisda and Rabah bar Rav Huna visited the Reish Galusa's house. Rav Nachman (the Reish Galusa's son-in-law) lodged them to sleep in a Sukah in which the decorations were four Tefachim below the Sechach. They did not comment.

Rav Nachman: This shows that you retracted!

Rav Chisda and Rabah bar Rav Huna: No. We are Sheluchei Mitzvah, so we are exempt from Sukah.

RISHONIM

The Rif brings our Gemara, and rules like the Rabim (Rav Chisda and Rabah bar Rav Huna against Rav Nachman).

Rosh (1:18): The Ritz Gei'us rules like Rav Nachman because he holds like Shmuel (who says that an Ohel Arai of less than 10 Tefachim does not disqualify Ohel Sukah). This is wrong; we cannot learn from there (Shmuel discusses Kosher Sechach; here we discuss Pasul Sechach). Noy within four Tefachim of the Sechach is Kosher, but Pasul Sechach disqualifies even within four. We learn from Rav Chisda and Rabah bar Rav Huna. They allow Noy only within four Tefachim of the Sechach, and (in the same place) a sheet to prevent droppings disqualifies.

Ran (DH umi'Ha): Rav Ashi said that a shirt hung in the Sukah to dry should be removed when it dries, because of Mar'is ha'Ayin. This implies that letter of the law what is done for the sake of the garment is like for Noy, and does not disqualify. The Yerushalmi says that a sheet for any reason other than droppings does not disqualify. Others say that if it is there for the sake of the garment it is not Batel to the Sechach, and it disqualifies. They explain that Rav Ashi allowed it to be there when they were not eating or sleeping. He said to remove it when it is dry, lest people say that he left it even at the time of eating or sleeping, and that something that is Mekabel Tum'ah may be used for Sechach. We are not concerned when it is wet, for surely people would not eat or sleep under a dripping garment.

This episode disproves R. Tam, who says that that Pasul Sechach cannot disqualify a Sukah that is already Kosher.

Note: Perhaps R. Tam would say that there was almost as much sun as shade, and we are concerned lest people think that the shirt is needed to comprise a majority of shade!

Ran (DH Itmar): When the Noyei Sukah are four Tefachim from the Sechach they are not Batel to it. Apparently, this is even if the Noy gives less shade than sun, for the Gemara did not stipulate. The Ro'oh explains otherwise.

Rambam (Hilchos Sukah 5:17): If one spread a sheet over it, or underneath to protect from droppings, it is Pasul. If he spread it for decoration, it is Kosher. Similarly, if it had enough Sechach, and he adorned it with fruits and Kelim it is Kosher, whether they hang from the Sechach or the walls.

Rambam (18): If Noyei Sukah are four Tefachim below the Sechach, it is Pasul. It is as if one who sits underneath is not under the Sechach, rather, under fruits and Kelim, which are invalid for Sechach.

Question (Lechem Mishneh): The Magid Mishnah says that the Rambam disqualifies even if the Noy gives less shade than sun. Why is this different than branches of Sechach which reach below 10 Tefachim? They disqualify a Sukah only because they make it unlivable!

Answer (Lechem Mishneh): The branches are Batel to the Sechach.

Rosh (1:16): Ge'onim say that the Mishnah disqualifies when a sheet was spread to protect when there was not enough Sechach without the sheet. If there was enough Sechach to give a majority of shade, Pasul Sechach does not join with it to disqualify it. R. Tam explains the Mishnah to say that if one spread a sheet over because of the sun, i.e. so it will not dry out the Sechach, or underneath because of things dropping, i.e. lest the Sechach be diminished. The sheet causes enough Sechach to remain to give a majority of shade, therefore it is Pasul.

Ran (DH Masnisin): R. Tam holds that Pasul Sechach cannot disqualify a Sukah that is already Kosher. This forced him to say that the Pasul Sechach is needed to preserve the Kosher Sechach. Most argue with R. Tam.

Question (Rosh, ibid.): (Rashi disqualifies when a sheet is spread to protect because it obstructs the Sechach.) Why is this difference than for Noy? When the sun shone on R. Eliezer's feet, R. Yehudah spread a sheet over the Sukah (27b)! According to the Ge'onim, why does the Mishnah distinguish between a sheet spread to protect or for Noy? In either case it is Kosher only if the Kosher Sechach alone gives a majority of shade! This is not difficult for R. Tam.

Answer (Taz OC 629:22): The Mordechai says that Noy is Batel to the Sukah, but something for the sake of man is not. This does not answer for the episode with R. Eliezer. Rather, it must be evident that it is not spread for the sake of Sechach. Even R. Tam permits only if the sun reached the Sukah, and it is evident that he spreads for shade. Rashi permits only if the sun reached the person.

Teshuvas Rashba (1:55): It is a Mitzvah to put nice Kelim in the Sukah to endear the Mitzvah and make dwelling there pleasant. If it is evident that they are not for Sechach it is permitted, like the shirt hung to dry.

POSKIM

Shulchan Aruch (OC 627:4): If one spread a sheet (underneath) for Noy, it is Kosher only if it is within four Tefachim of the Sechach. If it is not for Noy, it disqualifies in any case.

Kaf ha'Chayim (105): Some say that if it was spread temporarily it disqualifies only if it has a roof and is 10 Tefachim high.

Rema: One should be careful to hang all Noy within four Tefachim of the Sechach.

Mishnah Berurah (11): If it is four away one sits in the shade of the Noy, not of the Sukah. This is even if the Noy allows more sun than shade. Some permit in this case.

Mishnah Berurah (13): Letter of the law, we should be concerned only if the Noy is four Tefachim wide, like other Sechach Pasul. However, one should be careful even if it is less, lest he will have Noy four wide and sit under it. One should not be stringent about a lamp over the table. It is better to distance a lamp as far from the Sechach as possible (lest the Sechach catch fire).

Sha'ar ha'Tziyon (21): Even if the lamp is four Tefachim wide, we are not concerned because people do not sit under it.

Mishnah Berurah (12): If it is four wide (and goes across the entire length of the Sukah to the other) it disqualifies the entire Sukah.

Shulchan Aruch (629:19): If one spread a sheet over the Sechach to protect from the sun or underneath to shield from droppings, it is Pasul. If it is for Noy and within four Tefachim of the Sechach, it is Kosher. Some say that a sheet disqualifies only if it preserves the Shi'ur of Sechach, i.e. to prevent the sun from drying it out or to prevent parts of the Sechach from falling.

Beis Yosef (DH v'Yesh): The Tur rules like R. Tam, yet he disqualifies a Sukah under a tree even if the Sukah was there first! We must say that the Tur disagrees with the Ran who says that each of these depends on the other.

Shulchan Aruch (ibid.): L'Chatchilah one should allow a sheet only if it is clearly to protect (people, but not the Sechach), or if it is soaked and clearly it was spread to dry out.

Beis Yosef (DH Kosav ha'Roke'ach): One may spread a sheet around the Sukah for shade, even on Shabbos. One may not spread it under the Sechach even on Yom Tov, for this is making an Ohel. On top of the Sechach is forbidden even on Chol ha'Mo'ed, like Rav Ashi told his slave (to take down the garment).

Magen Avraham (25): Even if it is soaked it is forbidden to eat under it.

Mishnah Berurah (58): Even when it is clearly to protect, it is permitted only according to R. Tam. L'Chatchilah, one should not eat under it. If rain is dripping from the Sechach or wind is extinguishing the Neros, it is better to eat under a sheet than to eat outside the Sukah, but one should not bless Leshev ba'Sukah then.