The Rarest Blue

UnknownThe Rarest Blue
By Baruch Sterman with Judy Taubes Sterman
Lyons Press
Guilford, Connecticut, 2012
305 pages

Reviewed by Alfred Cohen

Speak to the children of Israel, and let them make for themselves tzitzit at the corners of their garments, for all generations. And they shall put . . . a strand of techelet . . . at the corner. And [when] you see it, you will remember all the mitzvoth of the Lord and do them . . .  (Exodus 15:37).

While the mitzvah of donning tzitzit is fairly straightforward—one must wear fringes at the corners of a four-cornered garment—the requirement to include a strand of techelet is somewhat ambiguous. What is techelet? What purpose does it serve? Elucidating the verse above, the rabbis state: Techelet is the same color as the heavens, and when a person sees it on his garment, he will remember God Who dwells in heaven and has given us commandments, and thereby he will be prompted to observe all the mitzvot of the Torah (Rashi, ibid.). [Interestingly, the blue stripe in the Israeli flag is evocative of the strand of blue in the tzitzit.]

For thousands of years tzitzit did indeed include the thread of techelet, but almost 1,000 years ago the practice lapsed because the knowledge of how to make techelet was lost. The blue strand in the tzitzit needs to be specifically techelet, the color of blue dye derived from the secretions or ‘blood’ of a sea creature called the chilazon, and the identity of the elusive chilazon was lost.

Around 120 years ago, an attempt was made to identify this creature and restore the practice of wearing techelet in tzitzit. The attempt, initiated by Rabbi Henoch Leiner (of Radzyn, Poland) and generally regarded as failing to correctly identify the chilazon, nevertheless succeeded in stimulating great interest in reviving the lost mitzvah. Numerous rabbinic and scientific studies have been undertaken to verify the true identity of the chilazon, and the story of that quest as well as full discussions of the scientific data which support that inquiry are the subject of a fascinating new book, The Rarest Blue, written by Baruch Sterman with his wife, Judy Taubes Sterman.

Ultimately, then, we must conclude that while in the realm of information and background this book performs an excellent and important service, it actually deals with only one part of the equation.

The Rarest Blue reports on a broad range of inquiries into the scientific aspects of determining which sea creature is indeed the chilazon, which the book identifies as the murex trunculus, based upon descriptions in the Talmud and in rabbinic literature. Furthermore, The Rarest Blue details the production methods, including how the potential techelet is extracted from the murex and how the dye is manufactured. The authors even delve into the question of how color is perceived by the human eye. Their comprehensive and absorbing discussions are an excellent review of the scientific studies associated with the attempt to restore an ancient mitzvah, which include not only determining which sea creature could be the chilazon, but also the surprisingly complex endeavor to replicate the ancient extraction and dyeing methods.

In addition, the Stermans offer the history of this whole undertaking and explain what Rabbi Leiner attempted to do and why many think he arrived at the wrong conclusion. Among those who differed with Rabbi Leiner was Rabbi Isaac Herzog, who later became the chief rabbi of Israel and wrote his PhD thesis on his own attempts to identify the chilazon. There are also those who contend that Rabbi Herzog was equally mistaken in his own analyses.

The Stermans’ research makes for entertaining reading and provides valuable information. The Rarest Blue is an indispensable source of information, both historical and scientific, for those interested in the possible restoration of the mitzvah of techelet in the modern age.

Nevertheless, despite its excellent qualities, this book is only a first step in the process of reviving the ancient mitzvah, if that is even possible. This is because halachah does not emerge from scientific inquiry alone, albeit scientific knowledge is certainly an essential component of the halachic process. There are actually two distinct and essential procedures in determining Jewish law. First, it is necessary to ascertain the realities of the situation, scientific or otherwise. Thus, before a rabbi can decide whether it is permissible to use an electrical device on Shabbat, he must understand how electricity works and how the particular device is to be used. Similarly, before he can decide whether something is kosher, he needs to know its ingredients and how it is manufactured. Every competent posek has his medical experts, psychologists, chemists and other experts who inform him of the technical realia of the issue he needs to determine.

Second, once he has clarified the facts, a posek then needs to apply the pertinent halachic rules to the question. While halachah has to be based on technical information, that information does not create the halachah. Jewish law is determined by examining the facts and thereafter applying appropriate legal and religious principles. Ultimately, then, we must conclude that while in the realm of information and background this book performs an excellent and important service, it actually deals with only one part of the equation, and not the definitive part at that.

On the question of wearing a thread of blue in tzitzit nowadays, dyed by those claiming that they have rediscovered the chilazon, a host of halachic issues arise—which this book does not address. To be perfectly fair, the authors never claim that their study offers a comprehensive rationale for renewing the wearing of techelet, nor do they claim to have any rabbinic knowledge. Their objective was only to present the scientific and historical background of the issue. The ultimate halachic decision is not part of their purview. On the other hand, their comprehensive study may well leave readers wondering why wearing techelet has not been embraced by the Torah-observant community on a grand scale, and that puzzlement arises from the fact that the halachic challenges are not alluded to. The authors should have at least mentioned that there are halachic issues that might preclude reinstating the wearing of techelet.

Firstly, identifying the murex as the chilazon is a conclusion challenged by quite a few; just as Rabbi Leiner was convinced that he had identified the correct creature, and it turned out that he had been defrauded, or that he deluded himself, it is quite possible that this latest identification might ultimately also be shown to be mistaken. One serious challenge to identifying the murex as the chilazon is that the Gemara portrays the chilazon as a creature that needs to be “hunted.” (The Gemara specifically defines the action of hunting on Shabbat as that which needs to be done to trap the chilazon.) Yet I personally saw the alleged chilazon resting quietly on the wall of the tank, from which it did not move for a very long time. It hardly seemed to necessitate hunting! Thus, the halachic discussion might well negate the scientific conclusions ancillary to identifying the chilazon.

Even setting aside the question of whether this newly identified creature is indeed the chilazon, there are those who challenge the underlying assumption that a mitzvah long forgotten may simply be revived. Thus, the basic premise of The Rarest Blue—that the mitzvah of techelet can be renewed in the modern age—faces a serious challenge. There are those who contend that a mesorah—a tradition handed down through the ages—is required in order to accept the identification of the murex as the chilazon, scientific proof notwithstanding. And even if it is accepted that the murex is the ancient chilazon, there remains the question of what shade of blue is true techelet: the Talmud describes the color of techelet as ‘resembling the sea; and the sea resembles the sky . . . .’ What color of blue is the Talmud talking about? Bright sky blue? Or the light blue of dawn? Or the purplish-blue of dusk? Each of these questions is debated by the rabbis and needs to be resolved before techelet can be accepted. These are issues debated by medieval rabbis (Rishonim), which would be a formidable undertaking to resolve.

Halachah is not decided by scientific information, but rather by weighing scientific information in the crucible of halachic principles. The authors have done a fine job of presenting the scientific background upon which a halachic ruling might be established. But by ignoring the far more important halachic discussion, they have, perhaps unwittingly, created an unfortunate impression that the scientific study is really all that counts; the implicit contention seems to be that if the data presented in The Rarest Blue holds up to scientific challenge, then it follows logically that the mitzvah of tzitzit with techelet can and should henceforth be observed using the blue dye from the murex. And that is certainly a false and misleading conclusion.

I am grateful to the authors for their valuable work, providing timely and important information about an arcane topic—information that will certainly be helpful to rabbis and laymen. But it is not the final word on the topic.

Rabbi Alfred Cohen is editor of the Journal of Halacha and Contemporary Society and the rabbi of Congregation Ohaiv Yisroel in Monsey. 

Listen to Dr. Baruch Sterman discuss the mystery of the chilazon at

This article was featured in the Winter 2013 issue of Jewish Action.
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