Ktav Stam

Ktav Stam (Hebrew: כְּתַב־סְתָ״ם‎) is the specific Jewish traditional writing with which holy scrolls (Sifrei Kodesh), tefillin and mezuzot are written.

The writing is done by means of a feather and ink (known as D'yo) onto special parchment called klaf.

Klaf is the material on which a sofer writes certain Jewish liturgical and ritual documents, the kosher form of parchment or vellum.

The writing material can be made of the specially prepared skin of a kosher animal – goat, cattle, or deer.

Maimonides wrote that the d'yo is prepared in the following way: One collects the soot of oils, of tar, of wax, or the like, and kneads it together with sap from a tree and a drop of honey.

The obligation primarily pertains to Sifrei Torah, Mezuza, and Meggila, however there are those who are similarly accustomed to placing sirtut on the Arba Parshiyot for tefillin.

The K'tav Ashuri is the only permissible Hebrew script, however over the centuries in Exile some minor variations have developed.

In tefillin and mezuzot all the letters, the words and the parashot are required to be written in the order they appear in the Torah.