Duchsustus
Duchsustus (Template:Langx, from Greek {{#invoke:Lang|lang}} dyschistos) is the name of a type of parchment used for religious writings in Judaism.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It is originally a Greek word and one of three Talmudic names for animal skin. The other two are Template:Transliteration and Template:Transliteration. The meanings of these terms, however, are the subject of controversy in Jewish law.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
According to the Talmud, a Torah scroll should, ideally, be written on Template:Transliteration, but may also be on Template:Transliteration; Template:Transliteration must be written on Template:Transliteration; and mezuzot may be written on Template:Transliteration, Template:Transliteration, or Template:Transliteration.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Template:Transliteration is the animal's dermis, Template:Transliteration is the epidermis, and Template:Transliteration is both layers tanned and unseparated.
Maimonides' prescriptions
There are halachic rules for the use of each of the three types of tanned skin.<ref name=MBM>Rabbi Moshe ben Maimon ("Maimonides"), "Tefillin, Mezuzah and Sefer Torah" - Chapter One, translated by Eliyahu Touger, on Chabad.org. Accessed 9 March 2024.</ref> According to Maimonides, Torah scrolls must be written on gevil only on the side on which the hair had grown, and never on duchsustos (understood as the half-skin from the flesh side).<ref name=MBM/> Phylacteries, if written on klaf, must be written on the flesh side.<ref name=MBM/> A mezuzah, when written on duchsustos, must be written on the hair side.<ref name=MBM/> It is unacceptable to write on the hair side of klaf or on the flesh side of gevil and duchsustos.<ref name=MBM/>