A few notes on Rashi in last week's parsha on the topic techeiles:
1) Color: Rashi (15:38) writes that techeiles is a “tzeva yarok,” which we would translate as green, or maybe greenish blue. Later in the parsha (15:42) Rashi quotes from R’ Moshe haDarshan that techeiles is a reminder of makkas bechoros, which took place at night, and therefore techeiles is a dark color like the night sky (midnight blue?) Chazal famously tell us that “techeiles domeh l’yam…,”suggesting it is a sea blue or sea green color, though the statement may be a figurative association rather than a literal description of the color. Rambam writes that the techeiles is the color of sky blue during midday.
2) Knots: Rashi quotes from the Tanchuma writes that tzitzis is a reminder of taryag mitzvos because tzitzis is gematriya 600 (Rashi is counting two yud’s in the word even though in the Torah it is spelled without those yud’s – see Gur Aryeh and others) + 8 strings and 5 knots = 613.
A little background to set the stage for what is difficult here: the gemara (Menachos 39) tells us that each set of tzitzis should have between 7 and 13 sets of windings (chulyos) with 3 windings of string (krichos) per set (this is how most Rishonim read it). The gemara also writes that one should have a knot between each chulya.
So how do you get 5 knots? There should be at least 8 knots if not more?
The simplest answer is that we don’t pasken like this Tanchuma (the Rambam does not quote it). Some Rishonim hold that the chulyos alternated between techeiles and white. If you leave off the three chulyos of techeiles and do only four of white, you would end up with five knots. Alternatively, the techeiles and white chulyos may have been paired together.
3) Number of strings: Rashi and Tosfos (Menachos 38) hold that two of the 4 complete strings (that are doubled to make 8) should be techeiles. Rambam holds only one string of eight is techeiles; Ra’avad says it is one complete strong of the 4.
Rashi (15:41) on our parsha quoting R’ Moshe haDarshan writes that tzitzis have eight strings corresponding to the eight days that passed from yetzi’as Mitzrayim until kri’as Yam Suf. Everyone asks the same question: kri’as Yam Suf took place seven, not eight days after yetzias Mitzrayim!
Meshech Chochma gives a simple answer: there is an error in our text of Rashi -- instead of 8, it should say 7. But don’t tzitzis have 8 strings? He explains that R’ Moshe haDarshan held like the shitas haRambam, that 1 of 8 strings is techeiles, leaving 7 that are white – these are the 7 strings that correspond to the 7 days that Rashi is talking about.
Meshech Chochma does not bring any proof for his textual emendation, but there may be evidence that he is right if you read Rashi on the first pasuk in Parshas Korach carefully. Rashi quotes from the Midrash that Korach’s followers dressed themselves in garments made entirely of techeiles and challenged Moshe to explain why these garments were obligated in tzitzis. “If ONE thread of techeiles is sufficient when the garment is of some another color,” they argued, “Then surely if the entire garment is made of techeiles there should be no need for tzitzis.” Unlike Rashi on the gemara, who writes that 2 techeiles strings are required, here Rashi seems to indicate that one string is enough.