In previous Halachot we have explained that is forbidden to tie a “permanent” knot on Shabbat, i.e. a knot which is not meant to be untied in the near future. It is likewise forbidden to tie a “professional” knot on Shabbat, i.e. a knot which requires some skill to tie. However, a knot which is neither permanent nor professional may be tied on Shabbat.
We shall now discuss the halachic definitions of “permanent” and “professional” knots.
A Knot Intended to be Untied within Seven Days
Some Rishonim write that any knot which is meant to exist for one day is considered “permanent” and may not be tied on Shabbat. The Maharam (quoted by the Tashbetz in Chapter 52) therefore writes that one may not untie the knot holding a robe and pants together (in those times, people would tie their robes to their pants and leave it like that for several days) since this knot is not meant to be untied every day. It is likewise forbidden to tie such a knot on Shabbat.
Others write that only a knot meant to exist for seven days is considered “permanent.” The Tur rules likewise. According to this view, there is no need for the knot to be tied for less than one day. Maran Rabbeinu Ovadia Yosef zt”l rules in accordance with this view in his Chazon Ovadia-Shabbat, Part 5, page 47.
Tying One’s Shoes
According to all opinions, however, one may tie one’s shoes in the manner we are accustomed to, for such a knot is not considered professional and one usually unties this knot every night when removing the shoes before bedtime.
A Double Knot
Regarding a “professional” knot, the Poskim disagree with regards to a double knot. When one ties one’s shoes, one usually makes one “knot” (the first crossing of the laces) and makes a bow on top of that. However, when one makes a second knot on top of the first one, the knot becomes stronger. Some consider this knot a professional one which may not be tied on Shabbat, for we are not quite clear about the distinction between a “professional” knot and a “layman’s” knot. They therefore rule stringently on this matter. The Shiltei Giborim and others rule likewise.
Nevertheless, others disagree with the Shiltei Giborim’s opinion and rule that a double knot is not considered a “professional” knot. Maran zt”l rules likewise (ibid. page 57) and writes that when there is a need, one may act leniently and tie a double knot on Shabbat. Only when one has another option should one act stringently.
Summary: A knot which one intends to untie within seven days is not considered a permanent knot. A double knot is not considered a professional knot. Any knot which is neither permanent nor professionally made may be tied on Shabbat.
In the next Halacha we shall summarize the basic points of this law.