Chapter 170 : Chapter 170 The Prohibition of Shaving the Hair of the Temples and Beard
§1
There are two "corners" of the head, located at the base of the (sides of) the head, at the juncture of the temple and the cheek, on both right and left sides near the ears. Even shaving [cutting these corners] with a scissors close to the skin as with a razor, so that nothing remains of the hair close to the skin, is forbidden according to some
Poskim. Therefore, if it is necessary to shave them for medical reasons, you should be careful not to shave close to the skin. The area of the corners that are forbidden to shave includes the hair from the top of the forehead to below the ear, at the point where the bottom jaw widens and spreads outward.
§2
The Torah forbids shaving the corners of the beard, only when done with a razor. The beard has five "corners" and there are many opinions as to what they are. Therefore, a God-fearing Jew, should not use a razor on any part of the beard, even on his upper lip or under the chin. There is no difference between a razor and a sharp stone which cuts the hair, such as pigment or pumice stone, which are also forbidden. Those who remove their beard by means of a cream prepared from lime and avirem, should be careful not to scrape off the cream with a knife, which might cut the hair; but they should scrape it with a strip of wood or something similar.