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Dear Rabbi Simon,
The third paragraph of the Shema commands us to place a thread of techeilet on each corner of tzitzit (Num. 15:38). So why don’t we find at least one string with a light blue dye on all tzitziot? These days, as far as I can tell, most tzitzit are all white. Why don’t we dye one strand of tzitzit with a techeilet colour as commanded in the third paragraph of the Shema?

Dear Tzvi
Thank you for your question.
As you say, the Torah prescribes a blue dye called “techelet” to be used as one of the strings on the Tzitzit (also for dyeing priestly garments, BTW; see Exodus 25:4).
However, the key observation is that Tzitzit are still fit for use even if they lack the blue string. The strings are essential; the blueness is a preference—if it can be achieved correctly.
Techelet was a bluish colour, obtained from the fluid of a sea creature called the chilazon (Tosefta Menachot 9:6). It is found on the coast of northern Israel, though there is a disagreement among scholars regarding what the chilazon actually is. Some say it is a snail, others say a squid, and some claim it is another type of mollusc.
At any rate, it is apparent from the Talmud that this particular dye was very precious. Because of its value, the Romans (who conquered Judea in 63 BCE) seized control of its usage. This caused the Jewish dyers to go underground. By 639 CE, at the time of the Arab conquest, the secret of techelet was lost altogether.
In the 1850s, Rabbi Gershon Henoch Leiner, the Radzyner Rebbe, began to search for the long-lost chilazon. What he came up with was a type of squid that he believed fit the Talmud’s description. Within a few years, thousands of the rebbe’s followers and admirers were wearing techelet. Many others, however, questioned the rebbe’s identification, and the matter quickly became hotly disputed in the halakhic literature of the time.
In 1913 Rabbi Yitzchok Isaac Herzog (Chief Rabbi of Ireland and later Chief Rabbi of Israel) discovered that the techelet dye of the Radzyner Rebbe included iron filings in the process. Rabbi Herzog ruled that this makes the dye synthetic – and thus unfit for use. Nevertheless, there are still people today who continue to wear the Techelet of the Radzyner Rebbe.
As Rabbi Herzog continued his research, he found that the French zoologist Henri de Lacase-Duthiers had discovered a mollusc called murex trunculus that could create a blue dye. Subsequent research has prompted other Jews to use Rabbi Herzog’s techelet.
Today, as you observe, the majority of Jews still do not wear Techelet because we don’t have a bona fide tradition extending from the time of the Sages of exactly which aquatic creature is used. Nevertheless, the techelet trend is gradually gaining traction, as you will notice at many shuls (including Kesher) in the mornings.
When you visit the Old City of Jerusalem, you can stop by the “Temple Institute” to see examples of wool dyed from the various sea creatures thought to be the Chilazon. To learn more, visit and (Be prepared for some nationalistic politics and a pervasive scent of messianism. But don’t let that put you off.)
I hope this is helpful.
Best wishes,
Rabbi Rashi Simon

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Ask the Rabbi: Quinoa on Pesach
Dear Rabbi Simon,
Where do you stand on quinoa (and the kitniyot ban) for Pesach?
Many thanks,
Dear Tzippy,
In line with other American authorities, I am in favour of quinoa. Although I reject completely the voices (mostly from Israel) seeking to abolish the ban on kitniyot entirely, IMO we do not need to include in the prohibition pseudo-grains that were unknown in the Old World until modern times. Best to buy with a Pesach hechsher though, to be free of any possible wheat contamination.
Rabbi Rashi Simon
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