Nazir 58b - Hair Removal

The Gr"a (Y.d. 182:1) cites 3 approaches to the issur of men to remove hair on their bodies. 1. Tosafos based on our girsa, paskening like Rav, hold that the entire issur is only m'drabonon. The underarm and erva hair cannot be removed with a razor, but can be removed with a scissors, and the hair on the rest of the body can even be removed with a razor. 2. The Beha"g based on an alternate girsa (with the girsa of the word "ela") holds that there is no distinction between the underarm/ beis haerva and the rest of the body. There is an issur with a razor but it is mutar with scissors. 3. The Beha"g based on girsa without the word "ela" so that there are 2 distinctions being made, between underarm/erva and the rest of the body and between scissors and a razor. Therefore, the first distinction that the braisa that says you receive malkus is for the underarm and beis ha'erva, implying that it is an issur d'oraysa. The second distinction is that for the rest of the body, with a razor it is an issur d'rabonon, and with a scissors it is mutar. Based on this last approach, the issur of shaving underarms and beis haerva with a razor could be an issur d'oraysa even if done with a scissors (but even if it is not d'oraysa it is at least assur even when done with scissors).

The Shulchan Aruch paskens like the last approach that the beis ha'erva and underarm are assur even with scissors and the other parts of the body are assur only with a razor.

Regarding shaving one's beard, the shulchan aruch writes that since there is a big dispute about the "corners" that are assur, one should not pass a razor over any part of their face. The Rama adds to this "even under the neck". Although there is an opinion cited in the taz and Gr"a that one of the "corners" may extend to the neck (i.e. the adams apple), the beis yosef and gr"a reject this opinion. However, there is a source to assur the area directly under the chin because the skin of the chin will sometimes stretch below the chin (but this will not extend all the way to the neck itself). Therefore, the only rationale to forbid a razor on the neck is because it is tantamount to shaving with a razor on the rest of one's body which is the opinion of Rabbeinu Yona. The Gr"a rejects this approach as well because the only issur of shaving the rest of one's body is for beautification purposes where hair doesn't grow very densely yet he want to beautify himself by shaving it as a woman would do, but shaving the area of the neck where hair grows densely and it is not customary for woman to shave that area at all, there is no issur whatsoever. L'ma'aseh it seems that one can rely on the gr"a and be matir shaving on the adams apple and the rest of the neck below with a razor like the gr"a, but it is better to be machmir for the shita of rabbeinu yona paskened by the rama.