OPINIONS: According to the Tana Kama in the Beraisa, one who traps ("Tzad") and smashes ("Potze'a") a Chilazon transgresses only one Melachah, the Melachah of trapping. According to Rebbi Yehudah, he transgresses two Melachos, trapping and Potze'a (a Toldah of Dash). One is not Chayav, though, for killing the Chilazon.

Many Acharonim point out that we can infer from the Sugya here a number of distinguishing features of the Chilazon. In addition to these features, there are a number of other distinguishing characteristics of the Chilazon mentioned in the Gemara, Rashi, and Tosfos elsewhere. Based on these Sugyos, is it possible to identify the Chilazon, and thus the Techeles dye? (For a more comprehensive survey of this topic, see Rabbi Mordecai Kornfeld's "Torah from the Internet," Shelach 5755, and see the special TECHELES SECTION of the Dafyomi Advancement Forum.)

(a) To address this question, we shall first list the characteristics of the Chilazon mentioned in the Gemara here and in other Sugyos.

The species: The first group of features describe the species of the Chilazon.

1. The Beraisa in Menachos (44a) says that "its creature is like a fish."

2. The Gemara earlier (74b) says that the Chilazon is captured with nets lowered into the water.

3. The Gemara here (75a) says that one is Chayav for Tzad (trapping) when he captures the Chilazon on Shabbos. This implies that the Chilazon is not a creature that is easy to catch, but rather it is a creature that runs away when one tries to catch it. We know that the Melachah of trapping applies only when one captures an animal that is able to flee and that tries to run away when it is being hunted (Beitzah 24a).

4. TOSFOS here (DH ha'Tzad) infers from the Gemara that one who removes a Chilazon from the sea on Shabbos is not held liable for killing it ("Netilas Neshamah") even if he allows the Chilazon to become partially dry (this is because the Chilazon does not die immediately upon being removed from the water, but it jumps around a bit. This is in contrast to the Halachah that one who removes a fish from water is considered to have killed it as soon as it becomes partially dry, since it will certainly die (Shabbos 107b). Apparently, there is some difference between the Chilazon and other sea creatures in this regard.

5. The Gemara discusses one who "smashes" ("Potze'a") a Chilazon to extract its dye. The word "Potze'a" implies cracking or pounding a hard surface, such as a person's bones or skull (Shemos 21:25, Sanhedrin 82a), or a nutshell or branch (Beitzah 34a), as opposed to "Kore'a" (ripping). From the use of this word to describe what is done to the Chilazon to extract its blood, it seems that the Chilazon has some sort of hard shell which needs to be "cracked open."

The details of the Chilazon: The next group of features describe specific traits of the Chilazon.

6. The Beraisa in Menachos (44a) says that that the Chilazon's body is like the sea (according to the text of the Beraisa in Maseches Tzitzis, its body is like the sky). This implies that the body of the actual creature has a bluish hue.

7. The Beraisa there says that "it comes up once every seventy years," or, according to the text in Maseches Tzitzis, once every seven years. The Beraisa mentions that the dye of the Chilazon is very expensive due to the infrequent availability of the Chilazon.

8. The Gemara earlier in Shabbos (26a) and in Megilah (6a) limits the locale in which the Chilazon is found to the seashores of the tribe of Zevulun, "from the cliffs of Tzur (Rosh ha'Nikrah) to Haifa."

The Chilazon's ink: The final group of features relate to the ink that the Chilazon produces.

9. RABEINU TAM, cited by TOSFOS in Kesuvos (5b, DH Dam), proves that taking blood out of a creature is forbidden on Shabbos because of Netilas Neshamah (killing). Tosfos asks that according to Rabeinu Tam, why is one not Chayav for the Melachah of Netilas Neshamah when one takes blood out of the Chilazon? Tosfos answers that the blood of the Chilazon is gathered in a separate sack in the Chilazon and is ready to be extracted, and therefore its removal does not diminish the Chilazon's life in any way.

10. The Gemara here says that if the dye is extracted from the Chilazon while it is alive, it is of a better quality.

11. The Gemara in Bava Metzia (61b) says that the color of Techeles that comes from the Chilazon is indistinguishable from that of indigo ("Kala Ilan").

12. The Gemara in Menachos (43b) says that Techeles is steadfast. It does not fade with time nor wash out of the wool dyed with it.

(b) Now that we have reviewed the characteristics of the Chilazon that can be derived from the Gemara's statements about it, we shall analyze the various opinions of the identity of the Techeles and examine whether these opinions are consistent with the characteristics enumerated above.

1. Is it a Kosher fish?

TOSFOS here (75a, DH ha'Tzad and DH v'Lichayev) implies that the Chilazon is a type of fish that squirms around in the net after it is caught, making it difficult to extract its dye. This, Tosfos explains, is the difference between the Chilazon and the other fish of the sea with regard to the prohibition of Netilas Neshamah on Shabbos (#4 above). Since the Chilazon squirms about after it is removed from the water, one is not considered to have killed it, and one has not transgressed the Melachah of Netilas Neshamah at the moment that he takes it out of the water. Rather, it kills itself by wriggling about.

It seems that the view of Tosfos, that the Chilazon is a fish, is based on the Gemara here (#2 above) which implies that the Chilazon is a fish like any other, and it must be captured with nets. The RAMBAM (Hilchos Tzitzis 2:2) also writes that the Chilazon is a fish. They do not discuss, however, the exact identity of this fish, or whether it is a Kosher or non-Kosher fish. The view that the Chilazon is a fish also conforms with features #1 and #3 enumerated above. Although it seems to contradict feature #5 since it does not have a hard shell and the word "Potze'a" does not seem appropriate, Rashi here avoids this contradiction by explaining that the word "Potze'a" in this context is used differently. It does not mean to "smash," but rather to "squeeze out" the dye-blood from the fish.

RABEINU BACHYE (Shemos 25:3) discusses the three dyes used in the construction of the Mishkan -- Techeles, Argaman, and Tola'as Shani. The last of these three dyes is generally understood to mean "scarlet from a worm." Rabeinu Bachye asks how this is possible, since the Gemara in Shabbos (28b) says that only products that are permitted to be eaten were used in the Mishkan. Worms and their secretions are not Kosher! He therefore explains that the scarlet dye of the Tola'as Shani was not actually taken from worms, but from some sort of berry in which the worms tend to live. According to the approach of Rabeinu Bachye, we may conclude that the Chilazon, which is a sea creature, must be a normal fish with fins and scales, for this type of fish is the only Kosher sea creature.

The approach of Rabeinu Bachye, however, is problematic. It seems clear from the Yerushalmi (Kil'ayim 9:1) that the scarlet dye of Tola'as Shani indeed was extracted from a worm (the Kermococcus vermilis, an insect that breeds on a certain species of oak), and not from a berry. This has also been verified from other historical and scientific sources.

Regarding how a non-Kosher creature could be used in the manufacture of an item for use in the Mishkan, we must say that it was only the actual materials used in the Mishkan which were subject to this rule, and not the dyes that were used to color them. The dyes, which are not tangible objects in the finished product, were not included in this prohibition. Accordingly, we are not bound to assume that the Chilazon was a Kosher creature. (See NODA B'YEHUDAH, Mahadura Tinyana OC 3.)

2. Is it a squid?

As we mentioned above, Tosfos maintains that the Chilazon is a fish. While Rabeinu Bachye asserts that it had to be a Kosher fish in order to be used in the Mishkan, other authorities assert that it did not need to be a Kosher fish; a dye obtained from a non-Kosher fish was also permitted to be used in the Mishkan.

In the late nineteenth century, Ludwig Lewysohn proposed in his book, "Talmudic Zoology" ("Die Zoalogie des Talmuds," Frankfurt 1858, pp. 284-5), that the Chilazon is a type of squid, known as the cuttlefish. Lewysohn based his conclusion on an inference from a statement of the RAMBAM (Hilchos Tzitzis 2:2). Shortly afterwards (circa 1888), the brilliant and dynamic Rebbe of Radzin, Rav Gershon Henoch Leiner, came to the same conclusion. He carried the conclusion one step further by actually developing a process whereby the sepia (inky secretion) of the cuttlefish, which normally produces a dark brown dye, was transformed into a blue dye. The Radziner Rebbe authored three large volumes intended to prove that he had indeed re-discovered the lost Techeles (SEFUNEI TEMUNEI CHOL, PESIL TECHELES, and EIN TECHELES), and he set up a factory where the dye was produced.

(It is interesting to note that the method used by the Radziner Rebbe to produce Techeles consisted of boiling the sepia together with iron filings and potash at extremely high temperatures to produce the pigment ferric ferrocyanide. Dye chemists are quick to point out, however, that this process does not make any unique use of the squid's inky secretion. In fact, the sepia itself disintegrates and never makes it to the final product, leaving behind only its nitrogen atoms. Any compound that contains nitrogen will produce the same result when boiled with iron. In fact, a similar process is used by organic chemistry students to test for nitrogen in compounds.)

The approach of the Radziner conforms with #2, #3, and #4, since he maintains that the Chilazon was a fish, as we pointed out earlier (b:1). (It conforms with #5 as well, because squids indeed have a hard, shell-like "bone" under their skin.) It also conforms with #9, because the ink (sepia) of the squid is contained in a separate sack. The ink is the blood that the Gemara mentions. It might conform with characteristic #10 as well. As for characteristic #6, perhaps the body can be described as "looking like the sea" since the cuttlefish is somewhat transparent, and changes color according to its environment.

However, there are a number of difficulties with the Radziner Rebbe's opinion. First, Techeles is described as absolutely indelible (#12 above), but the Radziner's Techeles can fade (a process called "bleeding") when scrubbed with common detergents. Second, the blue color that he produced was not the blue of the sea, the shade of indigo (#11), but rather a more metallic blue. Also, the squid he used is of a species that is relatively abundant and equally common in all oceans, and thus it does not correspond to the statements #7 and #8 about the rarity and limited habitat of the Chilazon.

3. Is it a snail?

RASHI in Sanhedrin (91a) writes that the Chilazon is a type of slug ("Tola'as"), which allows for the possibility of identifying it as a mollusk. Similarly, the RA'AVAD (Toras Kohanim Metzora 1:14) calls the Chilazon a type of worm or slug that lives in the sea.

This is also implied by the statement of the Beraisa in Menachos (#1 above). The Beraisa says that the body of the Chilazon looks "similar" to that of a fish, implying that the Chilazon itself is not a fish. The Beraisa also says that its "creature" is like that of a fish, which might refer to the slug inside of the shell, while "its body is like the sea" may refer to the color of the shell itself.

The YAD RAMAH in Sanhedrin (91a) implies that the word "Chilazon" refers to snails in general, and the Chilazon of the Techeles is a particular type of snail (see also ARUCH). This seems to be the way the RA'AVAD (at the end of his introduction to Sefer Yetzirah) uses the word Chilazon as well. Indeed, the word "Chilazon" is used in numerous places as a general term meaning a snail or a snail-like object. The Chilazon mentioned in Shir ha'Shirim Rabah (4:11) is clearly a creature that lives inside a shell. The Mishnah in Bechoros (6:2) and in Kelim (12:1) calls an object with a spiral or twisted snail-shell appearance a "Chilazon." In Sanhedrin (91a) we are told that Chilazons appear on the surface of the earth after a rain. It seems clear from all of these sources that the word "Chilazon" is used in the context of "snail," and it is therefore logical to assume that the Chilazon that produces Techeles is also a particular type of snail.

This is a very strong objection to the Radziner's identification of the Chilazon as a squid, as a squid does not live inside a shell. (The Radziner Rebbe's attempts to resolve this difficulty are recorded in "Ha'Techeles," p. 174.)

Identifying the Chilazon as a snail is consistent with characteristics #5 and #9. It also provides a simple explanation for why one is not obligated for Netilas Neshamah when he removes a Chilazon from the water. Removing a snail from water does not kill it, even if its shell dries out, since it can remain moist within the shell for a long period of time.

The problems with the snail hypothesis are characteristics #2 and #3 (as we mentioned before, b:1). The snail does not seem to require a net to be captured (#2), and it is not difficult to catch, as it does not run away (#3).

One answer for the characteristic that nets are used to catch the Chilazon (#2) is that historically and until today, the Greeks have hunted for snails by lowering baited nets into the water, into which the snails crawl to eat the bait. The nets are then lifted with the snails inside of them. However, this answer is not entirely satisfactory, since strings would serve this purpose just as well. From the Gemara it seems that the knots of the nets were important for the capture of the Chilazon.

Concerning the characteristic of trapping (#3), the Yerushalmi indeed states that one who captures the Chilazon is not Chayav for trapping. This makes sense only according to those who explain that the Chilazon is a snail (which does not flee when one catches it). Tosfos here (DH ha'Tzad) indeed grapples with the Yerushalmi's ruling.

To explain why the Bavli does obligate a person for trapping the Chilazon (if it is a snail), it has been suggested that since the snail hides itself in the sand and is difficult to find, capturing it is indeed considered to be the Melachah of trapping, even though it does not flee when found.

Perhaps a more plausible approach to these two questions is that the Bavli and Yerushalmi disagree with regard to the identity of the Chilazon. The Yerushalmi, which noticeably avoids the Bavli's suggestion that the Chilazon is caught in a net (Yerushalmi Shabbos 7:2), maintains that it is a snail. Therefore, one is not Chayav for Tzad if he captures a Chilazon. The Amora'im of the Bavli understand that the Chilazon is a fish, which is why they suggest that it is caught in nets and that one is Chayav for transgressing the Melachah of Tzad when one captures it. (M. KORNFELD)

It is interesting to note that Rashi in Menachos (44a, DH v'Olah) says that the Chilazon comes up "from the land." This does not fit the description of an aquatic snail. Indeed, Rashi himself in many other places (Sanhedrin 91a, DH Chilazon; Megilah 6a, DH Al Yedei; Bava Metzia 61b, DH Kala; Chulin 89a, DH she'ha'Techeles) says that the Chilazon comes up from the ocean.

The TAHARAS HA'KODESH explains that Rashi does not contradict himself. Rashi in Megilah states that the Chilazon comes up "from the ocean to the mountains." This means that Rashi understands that it originates in the sea, and from there it finds its way to the land. The YA'AVETZ explains that Rashi in Sanhedrin means that the Chilazon comes from the ocean floor, and thus when Rashi says "land," he means the land of the ocean.

4. Is it the Janthina snail?

Can we identify which of the many species of snails is the one that produces the Techeles dye?

The theory that the Chilazon is a snail was researched in depth by Rav Yitzchak Isaac ha'Levi Herzog zt'l, who laid the foundation for research into the identity of the Chilazon. The Chilazon was the topic of his doctoral thesis (at age 24), in which he combined his tremendous erudition in Torah with his exceptional scholarship in eight different disciplines and twelve languages. To this day, his thesis remains the most basic and authoritative work on the subject, from both a Talmudic and a scientific perspective. The Hebrew version of his thesis was reprinted in full in the book "Ha'Techeles" (by Rav Menachem Burstein, Jerusalem, 1988, pp. 352-437), an excellent work which summarizes all of the Techeles research done until that date. The longer, English version of Rav Herzog's thesis was printed in "The Royal Purple and the Biblical Blue" (Keter, 1987) along with other works on the subject.

Rav Herzog proposed that the snail from which Techeles was derived was the Janthina Pallida Harvey. It is found in the Mediterranean Sea, and has a beautiful violet-blue shell. When excited, it discharges a secretion of the same color. It is quite rare and lives in colonies that experience population explosions every four to seven years, when large numbers of them are washed ashore. This fits perfectly with characteristics #6 and #7, that the Chilazon looks like the sea and is rare.

In recent years, research has been done to determine whether a blue dye can be made from the Janthina's secretion. So far, the efforts have not met with much success. The secretion can produce a reddish-bluish color on a fabric, but within a matter of hours the color turns black. In addition, the dye washes right out of the fabric when brought into contact with water. The most advanced modern testing has not been able to even reduce the secretion in any chemical solution (the most basic requirement of any known dye). Instead of dissolving in liquid, the Janthina's ink forms a suspension. In this state, it cannot be induced to bind to a fabric. More research into the chemical makeup of the secretion is necessary.

There are other problems with identifying the Chilazon as the Janthina snail. First, like the cuttlefish, it is no more common along the shores of Zevulun than anywhere else in the Mediterranean (#8). Second, as Rav Herzog himself points out, no Janthina shells have ever been discovered in any archaeological site, nor is this snail mentioned anywhere in the Greek or Roman literature that discuss blue dye, indicating that it was not used in the ancient world.

5. Is it the Murex snail?

In the mid-1800's, archaeologists uncovered numerous ancient dye-producing factories along the Mediterranean coast, mostly in the north-eastern area, between Haifa and Lebanon, with large heaps of snail shells alongside them. This is consistent with the Gemara's statement (#8) that the only place in Eretz Yisrael where Techeles can be found is in the territory of Zevulun, which runs along the Mediterranean coast from Haifa northward. These shells have been identified as belonging to three distinct species of snails: Purpura Haemastoma, Murex Brandaris, and Murex Trunculus. It is now accepted that these snails were the source of Tyrian purple, the "Argaman" mentioned in the Torah.

Rav Herzog points out that it is clear from a number of Torah sources and historical sources that the Jews and the non-Jews extracted their blue dyes from the same creature ("Ha'Techeles," pp. 426-427; see also Shabbos 26a, and Rashi there, DH ul'Yogvim). Nevertheless, he rejects the suggestion that one or all of these species may be the true source of the Techeles for several reasons. First, the color of their shells is white, which contradicts the Gemara's description (#6 above) that the Chilazon's body is like the sea (a bluish hue). Furthermore, and more importantly, the dye extracted from these creatures is purple and not indigo (#11). The above-mentioned snails were clearly the source of Argaman, or "purpura" in Latin. Techeles, which is referred to in Latin by Josephus and Philo as "hyakinthos," may have been produced from another snail altogether -- perhaps the Janthina that he suggested (above, b:4).

Others (such as Alexander Dedekind in "Archeological Zoology," Vienna, 1898, p. 467) suggest that the blue dye of Techeles did come from the snails found near the ancient dye vats. Two of the species were used to produce Argaman, while the Murex Trunculus was used to produce Techeles. This distinction is based on the fact that not far from Sidon an ancient dyeing site was discovered, with two separate piles of shells near it. One huge pile contained a mix of shells of Purpura Haemastoma and Murex Brandaris, while the other contained only shells of Murex Trunculus ("Ha'Techeles, p. 421). Moreover, the Murex Trunculus produces a blue dye slightly more readily than the other two.

Although he personally favored his Janthina theory, Rav Herzog himself reluctantly admitted that, "The logical conclusion would certainly appear to be that the blue pigment produced by the Chilazon was obtained using the Murex Trunculus dye... it is highly unlikely that the Techeles Chilazon was not the Murex Trunculus" ("Ha'Techeles," p. 421).

Rav Herzog's main objection to this position was that the shells of Murex Trunculus are white and not similar to the sea (#6). Others explain that the Gemara which compares the Chilazon to the sea does not refer to the color of the snail, but to the wave-like contours on the snail's shell. Yet others explain that the Gemara's intention is to compare the snail's shell to the sea bed. The shell is covered by sea-fouling and perfectly matches the rocks to which it attaches itself. (However, neither of these explanations satisfies the version of the Beraisa that is quoted in Maseches Tzitzis, according to which the Chilazon is "similar to the sky." Another possibility is that when the Beraisa describes the "Guf" of the Chilazon, it is describing the ink which is used to produce its dye, and not its shell (-M. KORNFELD).)

Another objection Rav Herzog raised was that the secretion of the Murex Trunculus turns purple and not blue (#11). Rav Herzog himself raised the possibility that "there might have been some scheme known to the ancients for obtaining a blue dye out of this secretion" ("Ha'Techeles," p. 423). Recent research has shown that when the secretion is exposed to sunlight after being chemically reduced (a step in the dyeing process), the sunlight breaks down certain chemical bonds in the resulting liquid and it subsequently forms a blue dye. In fact, the resulting dye consists mostly of components bearing the exact same chemical composition as indigo.

One major difficulty remains. What is the once-in-seventy-years cycle of "coming up" mentioned by the Beraisa (#7)? Does the Murex Trunculus snail show any unusual prominence every seventy (or seven) years? So far, no such behavior has been observed in the Murex. Various explanations have been offered (for example, the Beraisa uses the number "seventy" merely to emphasize the infrequency of the appearance of the Chilazon, as the Mishnah in Makos (7a) uses that number to emphasize the infrequency of Beis Din's application of capital punishment), but no answer has yet been offered that is entirely satisfactory.

Today, there are two Techeles-producing factories. One, located in Bnei Brak, produces the Radziner Techeles, worn only by Radziner and Breslover Chasidim. The other, located in the Jericho area, produces Techeles from the Murex Trunculus (see TECHELES SECTION).

RAV CHAIM VITAL (in Sha'ar ha'Kavanos, Tzitzis, Derush 4) writes that Techeles represents Hash-m's presence as clearly felt in the world. This is why Techeles was widely accessible only during, and close to, the era when the Beis ha'Mikdash stood. At that time, Hash-m's presence was manifest in the world for all to see. After the exile, and subsequent hardships, when Hash-m's presence among His people has become less evident, Techeles has become "hidden" as well. The "return" of Techeles may be an indication that the manifestation of Hash-m's presence in this world, too, will soon return to its former state. (See also "Ha'Techeles," p. 186, note 21, and Likutei Tefilos 1:49). (M. KORNFELD)

(See also Insights to Menachos 44:1. Regarding the practical, Halachic implications of wearing Techeles today, see Insights to Menachos 44:2.)

QUESTION: The Gemara asks that when one captures a Chilazon, he should be Chayav not only for "Tzad" (trapping), but also for "Netilas Neshamah" (killing), since the Chilazon dies when it is caught. Rava answers that one is not Chayav for Netilas Neshamah when the Chilazon dies as a result of being caught, because his act is merely one of "Mis'asek" (he did one action, and another action occurred, unintended). The Gemara asks why the death of the Chilazon is not a "Pesik Reshei" (something which is definitely going to occur and thus is forbidden even if one had no intention for it to occur)? The Gemara answers that since one does not want the creature to die (because its blood makes a finer dye when extracted while the creature is alive), it is not a Meleches Machsheves and it is permitted.

Why does the Gemara not answer that one is exempt for killing the Chilazon because the act is "Mekalkel"? Since the act of killing is not done for a constructive purpose (such as to use the dead body of the Chilazon), even if it is a Pesik Reshei one should not be Chayav for it.

ANSWER: TOSFOS (DH v'l'Chayev) points out that Rebbi Shimon and Rebbi Yehudah argue whether "Mekalkel b'Chaburah" ("destructive" killing) is Chayav or Patur. Rebbi Shimon says that one is Chayav for an act of Mekalkel of Netilas Neshamah, and Rebbi Yehudah says that one is exempt, just as he is exempt in every other case of Mekalkel.

According to Rebbi Shimon, we can understand why the Gemara here does not simply answer that this act of Netilas Neshamah is Mekalkel and therefore one is exempt. Rebbi Shimon maintains that an act of Mekalkel of Netilas Neshamah is always Chayav. Tosfos explains that even according to Rebbi Yehudah, this act of Mekalkel would have been Chayav (had it been a Meleches Machsheves), because one accomplishes a slightly constructive purpose with the death of the Chilazon -- the extraction of its blood, which is more easily accomplished when the Chilazon is dead.