Is it appropriate to loosen and tighten the knot of tefillin shel yad each day?

The posuk says that one must tie (“ukshartam”) the tefillin on one’s arm. The Rishonim debate whether the knot must be retied every day or if a previously tied knot is sufficient.¹

The Alter Rebbe writes in his siddur that, after placing the shel yad on the arm and reciting the beracha, one should “tighten the strap in the knot to fulfill the mitzva of ukshartam.” Indeed, the knot invented by the Alter Rebbe includes a loop around the strap that can be loosened and tightened, unlike the loop used by others that always remains loose.²

A tradition held by many elder chassidim was that the advantage in the Alter Rebbe’s knot is the daily tightening of the loop, which satisfies the view that requires daily tying, and some even interpreted the instruction to “tighten the strap in the knot” as such.³ Other chassidim, however, claimed that they never saw this back in Russia,⁴ and the Alter Rebbe’s written instruction likely refers to tightening the bayis against the arm as implied from his subsequent words. In their view, the advantage of the Alter Rebbe’s knot is that it’s knotted (as opposed to other knots, which allow the retzua to move freely).⁵

The Rebbe is quoted as saying in yechidus that his father never taught him to loosen the loop daily, and in another instance, even expressed concern that tightening the loop after the bracha may be a hefsek. In yet a third instance, the Rebbe responded that, since he had not personally observed the Frierdiker Rebbe put on tefillin, the question of historical practice should be answered by those who had been in Lubavitch. When a bochur quoted his mashpia that daily tightening was the core chidush of the Alter Rebbe, the Rebbe replied that he may follow his mashpia’s guidance.⁶

When R. Leibel Groner submitted a written query to clarify how to conduct himself with tightening the knot, the Rebbe’s written response was “there is no directive from me to either side.” Similarly, the Rebbe refrained from giving clear guidance to others as well, and wrote to one of them that this is a question for Rabbonei Anash.⁷

See Sources (open PDF)