Kosheir – tying a knot – is one of the thirty-nine Melachos of Shabbos and most of its Halachos are concentrated in Perek v’Eilu K’sharim (15) in Maseches Shabbos. Forming certain types of knots violates an Issur d’Oraisa, others may only be a contravention of Issurei d’Rabbanan and are Patur Aval Asur, and still others are entirely permissible. In this series of essays, we will examine what constitutes a Kesher (a knot), forms of attachment that are not considered a Kesher, and when one can consider a Kesher to be temporary – a “Kesher l’Zman”. This essay will focus primarily on the Sugya and future essays will examine practical ramifications.
We will also examine several contemporary cases for features of Meleches Kosheir. These include cable ties, patient identification bracelets and tags, and twist ties for plastic bags. Does the strong attachment using these items mean that their use is a violation of Meleches Kosheir, or does the absence of an actual knot mean that they cannot be classified under the banner of this Melacha? From the physician’s perspective, questions of Meleches Kosheir most commonly arise in the context of suturing wounds.
The Essence of Meleches Kosheir
Is the definition of Meleches Kosheir that it is forbidden to create a “Chibur” (an attachment), or is it that it is forbidden to create a “Kesher” (a knot)? In other words, is the Melacha defined as attaching two separate and distinct items (such as two strings, or the two ends of a string), or would a person even be liable for forming a knot that does not tie two things together, such as a single knot on a string?
A related question arises with regard to the manner in which a knotted attachment is undone. If two things are usually detached by tearing them apart rather than untying the knot, does the fact that the Chibur of the two items is impermanent also mean that the Kesher should be considered impermanent, or is the Kesher considered to be permanent given that it remains in place even after the Chibur is detached?
The Rema (O.C. 317:1) cites the Semag who rules that it is forbidden to tie a knot in a single string, as a knot of this sort does not come apart. This implies that the definition of Kosheir is the creation of a Kesher rather than the creation of a Chibur.
However, Rav Nisim Karelitz zt”l (Chut Shani) contends that the Semag’s ruling only applies to a string which is made up of several, intertwined threads and where the knot is designed to prevent the threads from coming apart (like the knots that some make at the end of woolen Tzitzis strings). One would not be liable merely for forming a knot in a single thread.
One could perhaps challenge Rav Karelitz’ position from the Gemara in Shabbos (112a) that rules that one is liable for creating a Kishra d’Ushpechi. Rashi explains that this was a knot made on a shoelace to prevent it from slipping out of the shoe. Assumedly, this knot did not serve to join two parts of the lace together, and it was nevertheless prohibited since it prevented the lace from becoming detached from this shoe. The same is implied by the Mordechai (Shabbos, 386).
In fact, this would also seem to be the logical position. In all likelihood a person violates the Melacha of Kosheir by dint of the fact that he created a Kesher, provided that the Kesher is both beneficial and significant. Consequently, just as a person may not form a Kesher that ties two things to one another (as the outcome is beneficial), he may also not tie a knot that prevents his shoelace from escaping his shoe. It is only when a knot will provide no benefit whatsoever (such as a knot in a single piece of string), that tying it does not constitute a Melacha.
If we are correct in our assertion that Meleches Kosheir is defined as the creation of a knot, it would follow that a Kesher that is usually torn apart (rather than untied) should be considered a permanent knot since it will never be untied. However, Rashi implies otherwise. Based on the Gemara in Shabbos (157b), Rashi explains that it is permissible to make a knot in a material that will come apart of its own accord despite the fact that the knot itself may not necessarily come apart. This indicates that the essence of the Melacha is the creation of a Chibur, which is why one does not violate the Melacha when the Chibur will not last.
Perhaps a Kesher that is not designed to bring about a permanent attachment cannot be considered a permanent Kesher, even if the knot itself will remain intact for good. Rav Shlomo Zalman Auerbach zt”l (cited in Shemiras Shabbos Kehilchasa 35, footnote 67) makes this argument regarding a Kesher that is made in an item that will ultimately be discarded. We can certainly extend the same logic to something that a person will actually tear apart at a later date.
To summarize: The most straightforward definition of Meleches Kosheir is that “it is forbidden to create a knot.” However, that knot must serve a purpose. If it will be untied, then the action of the Melacha will ultimately be reversed and the knot cannot be considered to be permanent.
It follows that Meleches Kosheir is a Melacha where the purpose is an inseparable element of the Melacha, and without accomplishing that purpose, a person cannot be liable at all (see Tosfos, Shabbos 73b s.v. v’Tzarich l’Eitzim).
The Difference Between Tofeir and Kosheir
Rav Moshe Feinstein zt”l (Igros Moshe, O.C. 2:84) explains that the difference between the Melachos of Kosheir and Tofeir is that it is possible to undo the product of a Chibur made by means of Meleches Kosheir but not one made by means of Meleches Tofeir. The creation of a Chibur that cannot be undone is only a violation of Meleches Tofeir.
However, this doesn’t appear to be a logical distinction. If a person makes a complex knot that cannot be undone, why shouldn’t that be Meleches Kosheir? On the contrary, as stated earlier, the Gemara tells us explicitly that the Melacha d’Oraisa of Kosheir is specifically when forming a permanent knot – how can we suggest that a knot that cannot be undone is considered Tefira but not a Kesher? In addition, Tefira itself can often be undone!
An alternative approach is offered by both Rav Shlomo Zalman Auerbach zt”l (Minchas Shlomo 2:3) and Rav Nissim Karelitz zt”l (Chut Shani 34, p217). They contend that Meleches Tofeir is characterized by the attachment of two items so that they become one, whereas Meleches Kosheir is defined by the type of knot that is formed. If the knot will be permanent and never undone, it would be considered a Melacha; if it is intended to be undone, it is considered “Shimush” (usage of the items – e.g. fastening an item of clothing), not a creative act that could be deemed a Melacha.
A Nafka Mina between these approaches is the use of cable ties on Shabbos to attach two items together. From the perspective of the attachment, there seems to be no reason to say that a Kesher is only formed by looping one thread over another, and even soldering or welding could be considered a Tolda of Kosheir. However, in terms of the “knot”, since the cable ties cannot be undone, it would not meet the definition of a Kesher according to Rav Moshe zt”l. However, according to Rav Shlomo Zalman and Rav Karelitz zt”l, since this does not actually attach the two items together but merely ties them together, it would be considered Kosheir.
What Constitutes a Permanent Knot (a “Kesher Shel Kayama”)?
There are three types of knots that discussed with regard to Meleches Kosheir. The Mishna describes the two extremes. The most stringent case is that of a “Kesher Sapanin v’haGemalin” – knots commonly made by sailors or camel drivers. The most lenient case is that of a knot made to fasten clothes, which is permissible. The middle case (an “intermediate knot” which is forbidden but for which one isn’t liable – “Patur Aval Asur”) is described by the Gemara as a knot employed when fastening a long strap to the ring in the nose of a camel or when fastening a rope to the bow of a boat. This knot is considered temporary relative to those of sailors or camel drivers, but more permanent than those made to fasten garments.
The Gemara (ibid. 113a) also cites a dispute as to whether a bow is considered to be a Kesher or not. The Halacha is that it does not constitute a Kesher and may therefore be tied on Shabbos. Perhaps this Halacha is the basis to permit other types of attachment that are not regular knots.
There are three opinions among the Rishonim as to the definition of a Kesher Shel Kayama:
- Rashi and other Rishonim (listed by the Mishna Berura in his introduction to Siman 317) explain that a Kesher Shel Kayama is defined solely by the length of time that it will last. Rashi’s example of a Kesher Shel Kayama is the type of knots made in the threads of the coverings of the Mishkan(the “Yerios”) that were never undone. If a knot is not permanent, one would not be liable for tying it on Shabbos. Furthermore, it is permissible to form a knot that is intended to be untied that same day.
According to these Rishonim, the Melacha of Kosheir is unlike other Melachos d’Oraisa that are not defined by the permanence of their results. Furthermore, it should be obvious that even these Rishonim would agree that a knot that will never be untied but will disintegrate over time is still considered a Kesher Shel Kayama. “Permanent” only means that the knot will last for the duration of the life of the garment or thread. However, if a knot is made in a thread that is designed to dissolve, it would not be considered permanent as it is only intended to be temporary).
- The Rif and the Rambam hold that there are two criteria required in order to be considered a Kesher Shel Kayama. The first the type of knot – is it an expert knot (a “Kesher Uman”) or not? The second is the lifespan of the knot – will it remain permanently in place? If it is both an expert and permanent knot, one is liable for forming it on Shabbos. If neither criterion is met, it is permissible to tie it on Shabbos. If only one condition is in place, it is Patur Aval Asur (i.e., forbidden to tie on Shabbos but one would not be liable if he did).
- The Shiltei Giborim (Shabbos Perek 15, 1) deduces from the Rif that any extremely tight knot is considered a permanent knot. Therefore, a double knot is considered a “Kesher Uman” as the definition of Kesher Uman is not the expertise required to tie the knot but the strength of the knot itself. In fact, the Rema (beginning of Siman 317) rules that one is liable for tying a knot in a single string as that type of knot is usually very tight. This also appears to be the position of the Mishna Berura throughout the Siman.
This dispute also impacts the definition of an “intermediate knot” that is Patur Aval Asur. According to Rashi, any knot that will remain in place for an intermediate amount of time is an Issur d’Rabbanan. The Rema (O.C. 317:1) cites a dispute regarding how short the (intended) lifespan of a knot needs to be in order to be entirely permissible. Some hold that only a knot that would usually be untied on the same day can be tied on Shabbos, but anything intended to remain longer would be Patur Aval Asur. Others contend that as long as it will be untied within a week it is permissible to tie on Shabbos.
Perhaps this dispute is based on two different understandings of why a temporary knot is permissible. According to the first opinion, it is permissible to tie a knot that is defined as an act of “Shimush” and has no permanence at all. According to the second opinion, only a temporary knot is permissible, and as people commonly leave their clothes fastened for up to a week, such knots are considered temporary.
According to the Rambam and Rif, there are two knots that fall into the intermediate category: 1. An impermanent Kesher Uman. 2. A permanent but non-expert knot.
The Shiltei Giborim follows the opinion of the Rif (and Rambam), but adds a stringency. He holds that any double knot is considered a Kesher Uman. Therefore, even if one forms a temporary double knot, it would still be an Issur d’Rabbanan.
The latter Rishonim do not say how long a knot must last to be considered permanent, and it is not clear whether they would follow the opinion of Rashi and require that it be tied permanently to be an Issur d’Oraisa or that anything beyond immediate would be considered a Kesher Shel Kayama. However, the Poskim do not appear to distinguish between the Rishonim in this regard, and any knot that will not remain permanently in place will not be an Issur d’Oraisa, even if it is a Kesher Uman.
The Beis Yosef concludes that a knot that will remain in place longer than a week is considered permanent and an Issur d’Oraisa. However, the Mishna Berura does not cite this this and rules that there is only an Issur d’Oraisa if the knot is actually permanent. In fact, the source of their respective rulings is a comment of Rabbenu Peretz, cited by the Ravya, and as noted there, Rabbenu Peretz only uses the words “Kesher Shel Kayama” and does not actually define what this means. Moreover, as the Rema cites this very same expression (“Kesher Shel Kayama”) in the context of Issurei d’Rabbanan, it cannot be said that it certainly refers to an Issur d’Oraisa.
The Biur Halacha (317:4 s.v. sheEinam Kevuim) adduces proof from the Magid Mishna in the name of Tosfos who note that the Rishonim were accustomed to tying a bucket to a rope to lower into a well as they did not consider it to be a Kesher Shel Kayama as the bucket would often be removed. This proves that the knot needn’t be untied on the same day in order to be considered temporary, as long as it won’t remain in place for an extended period. The Biur Halacha therefore rules that, where necessary, one may rely on this position. Rav Ovadia Yosef zt”l held that Sefardim may even rely on this position and may tie knots intended to last up to a week l’Chatchila.
A Permanent Knot – The Source in the Mishkan
We have seen that according to Rashi one is only liable for Meleches Kosheir when forming a knot that is truly permanent.
The Gemara (Shabbos 74b) asserts that the source of Meleches Kosheir cannot be the fact that they would tie the sides of the Mishkan to pegs in the ground, as those knots were to be untied each time the Mishkan was dismantled. Rather, the source of the prohibition is the tying of the threads of the Mishkan’s covers (the “Yerios”), and those knots were permanent. This indicates that if one ties a knot but plans to untie it in the near future, it is not considered a Kesher. The Acharonim discuss at length whether this idea can be applied to all of the 39 Melachos or whether it is particular to Meleches Kosheir.
It is also clear from the Gemara that tying knots made in fishing nets also contravenes Meleches Kosheir even though they will be untied when the ropes are changed. This is because the knots would remain in place indefinitely until they are deliberately untied.
To be continued…
 As opposed to other Melachos, whose Dinim are spread across the entirety of Maseches Shabbos.
 Tying certain types of knots is permissible because knotting something is often just a form of “Shimush” (usage) and not a creative or productive act. Therefore, creating an impermanent knot is not a Melacha at all (see Shabbos 74b). However, with regard to other Melachos, it is forbidden even to create something temporary (as long as it is significant) as other Melachos are inherently creative and do not resemble “Shimush”. See our previous essays regarding Meleches Tofeir.
 See our previous essays on Meleches Tofeir for a discussion of whether suturing wounds on Shabbos is a violation of Meleches Tofeir.
 An alternative explanation as to why Kishra d’Ushpechi was forbidden is that the knot in the lace could be considered to be attaching the lace to the shoe. (However, one is liable for tying the knot in the lace even before it is inserted in the shoe. See the Mirkeves haMishna, Shabbos 10.)
 See Sefer Minchas Ish (15:7).
 The Acharonim discuss whether this depends on the intention of the person tying the knot, and therefore, if he does not intend for the knot to remain in place permanently then it is not considered a Kesher Shel Kayama, or whether it depends on how long this type of knot commonly remains in place. (In fact, according to the Beis Meir, there needs to be a reason why this particular knot will certainly be untied in order not to be considered a Kesher Shel Kayama.)