6695 —קביעת מועד החלאקה כאשר יום ההולדת חל בראש חודש

Shalom u'Vrachah!

... Regarding what you wrote about the day for cutting the hair, since the birthday falls on Rosh Chodesh. It is known according to the will of Rabbi Yehudah HaChassid that one should not shave on Rosh Chodesh.

And even though, seemingly, one could say: a) This refers specifically to shaving (as in the language of the will, and so too in Magen Avraham at the end of the section), but getting a haircut is permitted. b) That a three-year-old's haircut is different because it is a significant matter in Jewish custom—as my revered father-in-law, the Rebbe, said; see also Sha'ar HaTziyun to Shulchan Aruch Orach Chaim at the end of section 531—nevertheless, since the Alter Rebbe's wording (at the end of section 61) is 'to get a haircut,' and that it is due to a concern for danger (and not a prohibition), and that this haircut is not an actual mitzvah (see Shulchan Aruch HaRav Orach Chaim section 355:15-16)—one does not remove oneself from doubt. In my opinion, it should be done (immediately) after Rosh Chodesh.

Printed in Likkutei Sichos vol. 13 p. 265.

Summary

The Rebbe writes that when a child's third birthday falls on Rosh Chodesh, the upsherin should be scheduled immediately after Rosh Chodesh out of caution for Rabbi Yehudah HaChassid's directive, as this custom does not override potential concerns.