GEMARA

(Mishnah): One who is Makif Pe'os ha'Rosh (cuts the sidelocks) receives two sets of lashes, one for each. One who shaves the corners of the beard receives five sets of lashes, for two corners on each side and one below.

Makos 20b (Beraisa): Pe'as ha'Rosh is the end of the head.

This (Hakafas ha'Rosh) is making the sideburn even with the hairlines on the forehead and in back of the ears.

20a (a reciter of Beraisos): The one who cuts and the Nikaf (the one whose hair is cut) are both lashed.

Objection (Rav Chisda): Why is the Nikaf lashed? He did not do anything! Your teaching is like R. Yehudah, who says that one is lashed for a Lav she'Ein Bo Ma'aseh (but the Halachah does not follow him)!

Answer #1 (Rava): It is even like Chachamim. It teaches that one who cuts his own Pe'os is lashed twice (for each).

Answer #2 (Rav Ashi): It is even like Chachamim. The case is, he moves his head to help the one cutting. This is an action.

(Mishnah): He is liable only if he used a razor;

R. Eliezer obligates even if he used Melaket or Rehitani (a carpenter's plane or tweezers).

21a (Beraisa) Suggestion: Perhaps "u'Fe'as Zekanam Lo Yegalechu" obligates for shaving with scissors!

Rejection: One is liable for "v'Lo Sashchis" only if the entire hair is removed.

Suggestion: Perhaps one is liable for removing the hair with Melaket or Rehitani!

Rejection: "Lo Yegalechu." He is liable only for shaving that removes the entire hair, i.e. with a razor.

Question: Why does R. Eliezer obligate for Melaket or Rehitani? If he learns the Gezerah Shavah "Pe'as-Pe'as" (to equate "v'Lo Sashchis" written about Yisraelim to "Lo Yegalechu" written about Kohanim), he should obligate only for a razor. If he does not learn the Gezerah Shavah, he should obligate also for scissors!

Answer: He learns the Gezerah Shavah. He holds that also Melaket and Rehitani shave.

Nazir 41a (Beraisa) "Zekano" teaches that a Metzora shaves also his beard, even if he is a Kohen.

"Rosho" teaches that an Aseh overrides a Lav, and that Hakafah applies when one cuts all his hair, but it does not teach that a Metzora must shave with a razor. Therefore, "Zekano" is also needed.

RISHONIM

Rif and Rosh (Makos 4a and 3:2): We answered that the Nikaf is lashed if he helped. This is an action.

Nimukei Yosef (DH Zeh ha'Meshaveh): R. Yeshayah says that one is liable only with a razor, like the beard. We learn a Gezerah Shavah Pe'as-Pe'as from the beard. Also the Rambam says so.

Rambam (Hilchos Avodah Zarah 12:1): One may not shave Pe'os ha'Rosh the way idolaters used to. One is liable for each Pe'ah. Therefore, if one shaves both temples even at once with one warning, he is lashed twice. This is whether he shaves only the Pe'os and leaves the hair of the head. He is lashed, because he shaved the Pe'os. One who is shaved is exempt, unless he helped.

Ra'avad: Even if he did not help, since he was willingly shaved, he transgresses a Lav.

Rambam (6): Chachamim did not give a Shi'ur how much must be left. We heard from our elders that he may not leave less than 40 hairs. One may cut them with a scissors. Only shaving with a razor is forbidden.

Beis Yosef (YD 181 DH Kosav ha'Rambam): Some texts of the Rambam require leaving four hairs. Semag questioned this from a Tosefta (Makos 4:4) which says that one is liable for detaching two hairs. What is his question? The Rambam discusses how much one must leave, and the Tosefta discusses the Shi'ur to be liable!

Darchei Moshe (3): The Tosefta connotes that one is liable for two hairs even if he leaves many. This is difficult for the Rambam! The Beis Yosef must understand that it discusses only when there are only four hairs.

Beis Yosef (DH Aval): However, what is difficult for the Rambam is the Beraisa that says that Hakafah is cutting the sideburn even with the hairlines on the forehead and in back of the ears. This leaves much more than 40 hairs! Perhaps the Rambam teaches the width that one must leave. In any case one may shave some of the width, for this does not even the hairline.

Rosh (Makos 3:2): R. Eliezer requires a razor to be liable only for the beard, but one is liable for the Pe'os even without a razor. The Gemara connotes like this. It said that Hakafas ha'Rosh is evening the sideburns with the hairlines on the forehead and in back of the ears. It did not mention shaving, like it did regarding the beard, for one is liable for any way he evens it. Nazir 41a supports this. "Zekano" permits a Nazir to shave his beard. We infer that a Metzora must shave with a razor. If he could shave with scissors, we would not need "Zekano". The Gemara said that we cannot infer this from "Rosho" (which permits Hakafah). This shows that Hakafas ha'Rosh is even with a scissors, so even if a Metzora could shave with scissors, we would need "Rosho" to permit this. Only Zekano teaches that a Metzora must shave with a razor, for only the Isur to cut the beard is only with a razor. A Tosefta says that one is liable for Pe'os ha'Rosh only with a razor. It means (even) with scissors as close as a razor.

POSKIM

Shulchan Aruch (YD 181:1): There are two Pe'os. The end of the head is where it joins with the jaw, on the right and left.

Beis Yosef (DH u'Pe'os): Rashi explains that there are two parts to the head: the place of the hair, and the place of the face and beard. They join in front of the ears on each side.

Shulchan Aruch (2): One is liable whether he shaves only the Pe'os, or the entire head with the Pe'os.

Beis Yosef (DH v'Ein Chiluk): Nazir 58a concludes that all agree that one is liable for shaving the entire head.

Shulchan Aruch (3): One is liable only if he shaves with a razor. Some forbid with scissors like a razor. One should be concerned for their opinion.

Beis Yosef (DH v'Chosav): Semag and the Nimukei Yosef in the name of R. Yeshayah obligate only with a razor. The Mishnah says so Stam; it seems that this applies (not only to the beard, rather,) also to Pe'os ha'Rosh. A Tosefta explicitly says that one is liable for Pe'os ha'Rosh only with a razor. It seems that without a razor it is permitted l'Chatchilah. Tosfos, R. Yerucham and Semak forbid with scissors like a razor, like the Rosh.

R. Akiva Eiger (Shevuos 2b DH v'Ayen): If one leaves the hairs long enough to bend the end back to the root, this is not called Hakafah, for he does not make the hairline even. Tosfos (DH Chayav) forbids Hakafah using tweezers. Why may one comb the Pe'os? It is a Pesik Reshei (inevitable result) that this will uproot hairs! This requires investigation.

Pe'as Zekanecha (p.19) cites ha'Gaon R. Y.S. Elyashiv Shlita to say that surely it suffices to leave five millimeters, so one may use a shaver with a plastic attachment that ensures that hair will not be cut shorter than this. L'Shichno Sidreshu (1 p.300) says in the name of 'the Poskim' that surely six millimeters suffices.

Shulchan Aruch (4): Also the one who is shaved is liable of he helped, i.e. he tilted his head towards him to cut the Pe'os. It is forbidden even if he does not help, therefore, one may not be Nikaf even through a Nochri.

Beis Yosef (DH v'Chosav): Sefer ha'Mitzvos and Tosfos say so.

Shulchan Aruch (9): The Shi'ur of the Pe'ah is even with the hair on the forehead, until below the ear, where the lower jaw goes out and separates. One should not touch (i.e. cut) any of the hair in this area.

Beis Yosef (DH v'Nir'eh): It is a Safek mid'Oraisa, so one should not cut with a razor or with scissors like a razor from the forehead, until below the ear.