Head-Covering IV: How כיסוי ראש (ד): איך

Responsa Iggerot Moshe EH I:58

The fundamental prohibition was said in Ketubot 72b, as was taught in the beit midrash of Rabbi Yishmael from the verse “and he uncovered the head of the woman” –”an admonition to the daughters of Israel that they not go out with head uncovered [emphasis added]” and it is not said, “an admonition that they not go out with hair uncovered ” This implies that [the prohibition of going uncovered] depends on what is considered uncovering the head overall…It is also clear that one should only derive from the verse a prohibition [of uncovering] what the kohen needed to uncover of the head of the sota…for one could also say that [uncovering] less than that would not be a disgrace [to the sota] at all…Even if we say that we don’t need all of it [the head uncovered as part of the sota ordeal, and covered beforehand], in any case at least a large part of the head needed to be uncovered [during the ordeal, and covered beforehand]…This is the majority of the head or, at the very least, close to a majority of the head.

Meiri, Beit Ha-bechira, Ketubot 72a

Even though in most places its [kalata‘s] meaning is a small basket in which she places her spindle, here it seems to mean a sort of cap of rough fabric that she dons at night.

Responsa Maharam Alashkar 35
This statement that “the hair of a woman is erva” only deals with hair that a woman’s practice is to cover…In the [Talmud] chapter Chezkat Ha-batim, we say, “a woman does all her adornments and leaves out a little bit.” What is it [that she leaves out]? Rav says ‘bat tzida’” …This is the very custom of women today, that the woman binds all her hair and leaves out hair at the temples going down beside her face and this is called in the language of our sages ‘bat tzida,‘ as was explained…Our sages were lenient in many matters, so that a woman would not become unappealing to her husband

Letter, Rav Ovadya Yosef, Otzar Dinim 37:15, note 15 (cited Et Tzenu'im Chochma 79a)
That which some say, that even one hair from the hair of her head that is visible entails a Torah level prohibition, is incorrect, for the custom of Sefardi women is to show a fingerbreadth or two from the hair of the head in the front, and Maharam Alashkar, who was a world-class scholar in the time of Beit Yosef, ruled to permit it.

Responsa Iggerot Moshe EH I:58
Since the entire head is [defined as] a typically-covered area [which can give it erva status], one should prohibit [a man’s seeing it during Shema etc.] due to erva like [other] typically-covered body parts…Therefore, since in the law of typically-covered areas there is a distinction between a tefach and less…this distinction also applies to hair…Therefore one should not prohibit if she wants to reveal [hair]…but only two [etzba’ot] fingerbreadths in height, since the face is about two tefachim wide so that altogether it will be less than a [square] tefach. More than that is prohibited.

Responsa Iggerot Moshe EH I:58
Therefore according to halacha, even though it is proper for women to be stringent and cover [fully]…It is clear that those who wish to be lenient… should not be considered in violation of dat Yehudit God forbid, and even a talmid chacham and fearer of Heaven should not refrain from marrying such a woman if she fears Heaven and is careful about mitzvot and is of good character

Responsa Si’ach Nachum 105
But also when a covering is required, if a small amount of the hair emerges outside the covering, that’s also fine, …and in Beit Yosef there he cites the Rashba in the name of Ra’avad: ” Her face and hands and feet… and her hair outside of her hair-binding, which isn’t covered—we aren’t concerned about them” ….In summary, according to basic halacha one must cover most of the hair of the head, but it is permissible to leave out a bit of hair, and not specifically a certain amount of hair, but as is customary in the community of those who keep Torah and mitzvot to which she belongs.

Shiltei Gibborim to the Rif, Shabbat 29a in Rif pagination
It seems one can bring proof and support from this for women who go out with their own hair covered when they are married, but instead of the braid of their hair they wear the hair of other women…It clearly implies that the daughters of Israel are permitted to adorn themselves with these. For the statement ‘a woman’s hair is erva‘ refers only to the hair that is really attached to her scalp, when her scalp is visible with the hair. But with hair that covers her hair, there is no problem of ‘a woman’s hair is erva‘ here and also no [concern] of an uncovered head…even though it is an adornment for her in order to look like [she has a lot of] hair, there is no [halachic objection] to it…

Responsa Yabi'a Omer EH 5:5
For in past generations, the wigs were very visibly recognizable, and there was no concern of mar’it ayin [appearing to violate a prohibition], since they resemble natural hair. But the new wigs today, not only do they resemble natural hair, but they even exceed it in beauty and form and appearance, until even immodest women use them for adornment and beautification. And since there is no recognizable difference between these wigs and natural hair, certainly there is a concern of mar’it ayin …And the basic halacha is like the words of most if not all the later halachic authorities cited above to prohibit this, and it is a great mitzva to publicize the prohibition in public, especially for Sefardi women who have always been accustomed to prohibit…