When engraving the date on a Bar Mitzvah gift, do you put on the birthday or the date of Bar Mitzvah celebration?
There is no hard and fast rule here, since there is no established custom about engraving such gifts (although it is surely a nice thing to do). Yet, I think it makes the most sense to engrave the boy’s Hebrew birthday, since that is the day of his becoming an actual “Bar Mitzvah.” Additionally, I think you should also engrave the Torah portion of the Shabbat following the Hebrew birthday (like “Parshat Vayishlach”), which is when Bar Mitzvah boys are usually called up to read from the Torah.
Mazal Tov!
Shlomo Shulman