Rava explains that the top knot on the tzitzit (after all the windings) must be of Torah origin. If it were not, the attachment would be considered temporary, and there would be no need for the Torah to permit the use of mixed types (shatnez—wool and linen) in tzitzit.

Raba bar Rav Ada transmitted in the name of Rav that if a single thread is torn at its base (the top of the tzitzit), the tzitzit are no longer valid. When Rav Nachman taught this, Rava raised a challenge from a braita, but Rav Nachman reinterpreted the source in a way that resolved the contradiction.

Raba stated in the name of Rav that the specific thread used for the windings counts as one of the required threads of the tzitzit. Rav Yosef corrected the attribution, noting that the statement actually originated from Shmuel. Raba taught in the name of Shmuel that if the techelet thread was mostly consumed by the windings, leaving only a small amount of string to hang down, the tzitzit remain valid. Rav Yosef again corrected him, clarifying that this statement came from Rav.

Rav is quoted by another source as establishing the halakha on three points: a minimum of set of one windings is necessary, and the ideal tzitzit consists of one-third windings and two-thirds hanging string. According to Rebbi, each winding (chulya) should of one thread wound at least three times. However, a different braita states there should be between seven and thirteen windings, representing the seven firmaments and the spaces between them. One should also begin and end the windings with a white string, as derived from the biblical verse.

Rav and Raba bar bar Hana disagree about whether a garment with only windings and no loose strings hanging is valid. Their debate is rooted in different ways of understanding the purpose of the terms petil and gedilim used in the Torah.

Shmuel says in the name of Levi that even the white threads can be made of wool when placed on a linen garment. A question is then raised as to whether a woolen garment can have linen threads; Rav Yehuda's statement is cited to answer this, as he explicitly permits linen strings in a woolen garment. He even permits using both wool and linen strings in a silk garment. Rav Nachman disagrees with this last point and exempts a silk garment from tzitzit entirely. Rava challenges Rav Nachman's position, but Rav Nachman resolves the difficulty. Their underlying dispute is whether the word beged (clothing) in the Torah refers to all materials or only to those made of wool or linen.