The mitzvah of techelet is the commandment to wear a blue thread (ptil techelet) on the tzitzit, the tassles added to a four-cornered garment, as prescribed in the Torah. The Torah source for this mitzvah can be found in Numbers (Bamidbar) 15:38-39, which you may recognize as the 3rd paragraph of the Shema:
“Speak to the children of Israel and say to them that they shall make for themselves fringes on the corners of their garments, throughout their generations, and they shall affix a thread of sky-blue [techelet] on the fringe of each corner. This shall be tzitzit for you, and when you see it, you will remember all the commandments of the Lord to perform them, and you shall not wander after your hearts and after your eyes after which you are going astray.”
For many centuries, techelet was an essential part of tzitzit, and its use was widespread among Jewish communities using the material . However, at some point in history, the knowledge of how to produce the authentic techelet dye was lost, and the tradition of using techelet on tzitzit faded away. As a result, most men no longer wore techelet on their tzitzit, and tzitzit fringes were typically made with white threads only. This is true on both the tallit and the tzitzit worn for normal daily use, known as the tallit katan.
In recent times, the issue of reintroducing techelet has gained attention and sparked debates within the Jewish community. Some groups, particularly the Dati Leumi (National Religious) community, have revived the use of techelet on their tzitzit, basing their decision on historical and halachic research.
The controversy surrounding the identification of techelet primarily revolves around the specific source of the dye. The Talmud mentions that techelet comes from the “blood” of a sea creature known as the chilazon, but it does not provide a clear description of this creature, making it challenging to identify it with certainty.
In recent times, several researchers and experts in Jewish law have proposed different candidates for the chilazon, and the snail Murex trunculus has emerged as the most likely candidate. This snail, found in the Mediterranean Sea, produces a purple-blue dye that closely matches the descriptions of techelet in the Talmud.
R’ Gershon Henech Leiner of Radzyn, a prominent 19th-century Hasidic leader, was among those who attempted to identify the chilazon and revive the use of techelet. He believed that the dye from the cuttlefish was the authentic techelet, but his identification was met with opposition and skepticism from other Jewish scholars.
Today, some individuals who choose to wear techelet tzitzit follow the identification of Murex trunculus as the chilazon and believe that using techelet enhances the fulfillment of the mitzvah of tzitzit. However, it is important to note that this remains a matter of personal choice but particularly community interpretation, and not all Jewish communities or individuals agree on the discovery. While the mitzvah is significant, many do not wish to tie themselves to an interpretation that is more costly and complex without being certain, and without having any such established tradition.
For those who do choose to wear techelet tzitzit and accept the identification of the Murex trunculus as the source, they adhere to the principle that if one wears techelet tzitzit, they should not wear tzitzit without the ptil techelet, meaning that if they get a new tallit or tallit katan, this should only be worn if it has the techelet.
The tradition of using techelet on tzitzit was lost over time, but some groups, particularly the Dati Leumi community, have revived this practice based on historical and halachic research. The identification of the chilazon and the exact source of techelet dye have been subjects of debate, but the snail Murex trunculus is the most widely accepted candidate. However, the use of techelet on tzitzit is dependant upon the community norms, and one should always speak to a rav before making that decision.
