Date: 16 Sivan 5599
From: Rabbi Moshe Sofer
To: Unknown recipient
The Chasam Sofer systematically clarifies the levels of hair covering required of a married woman in public, in a courtyard, and in private, and whether the small row of hair at the temple may be left exposed. He rules that all hair requires at least a kerchief even in private, with a hat additionally required in public, and that in European communities the Zohar's stringency against exposing even the temple hair is binding custom that overrides the Talmud's apparent leniency.
Source: Shu"t Chasam Sofer OC §36