Q) I recently attended the giving of a Sefer Torah, and was invited to write a letter for a donation. The letters were already outlined in ink, I just filled in the blank inner space, isn’t that letter kosher anyway, if so what is my mitzvah?

A) There are different opinions in the Poiskim as to what exactly is the mitzvah of writing or fixing an already written letter in an almost finished Sefer Torah. There are those who support this minhag, claiming it is based on the Talmud (Menochos 30a) “if someone fixes even one single letter, it is tantamount to having written the whole Sefer”. In Shulchan Aruch (Y.D. 270,1) Remah rules that this applies only if one owns the Sefer or paid to have it written on his name. Writing a letter on someone else’s Sefer does not qualify. (Mikdash M’at 270,6 – Mishnas Avrohom 1,25) However some argue that paying for the letter makes him a partner in the Sefer and he fulfills the mitzvah of K’sivas Sefer Torah, according to the Poiskim that maintain that partnership is acceptable in the fulfillment of this mitzvah (ibid. – Nitey Gavriel, Ksivas Sefer Torah 13,1)

Horav Chaim Kanievsky Shlit”a, when asked this same query responded similarly. Unless he owns part of the Sefer, there is no mitzvah at all. He suggested filling in the letter “yud”, since without the inner ink filling, it could be read as a small “samech”. (Derech Sicho, Shoiftim)

Horav Shlomo Miller’s Shlit”a opinion is that there is at least a mitzvah in honoring and beautifying the Torah, by filling in the letter, even if it was already outlined and could be kosher as is.

Rabbi a. Bartfeld as revised by Horav Shlomo Miller Shlit”a