Kusti

The kusti is a sacred cord, woven flat and hollow from seventy two strands of lambswool, a number read as corresponding to the seventy two chapters of the Yasna, the central liturgical collection of the Avesta. It is wrapped three times around the waist over the sudreh and fastened with a sequence of ritual knots at the front and back rather than tied off casually. Lambswool is specified rather than any other fiber, and traditional practice ties this to the animal's standing in Zoroastrian ethics as a creature of Ahura Mazda under the wearer's care.

The cord is woven by hand, historically by women of priestly families, on a small fixed loom, and the physical count of the threads is meant to be perceptible to the fingers so that the retying can be performed correctly without needing to see it, which matters because the kusti is retied as part of prayers said before dawn and in low light. Boyce's survey of Zoroastrian textual and devotional sources situates the seventy two thread count among a wider set of numerically encoded garments in the tradition, where the object itself is built to carry a piece of doctrine in its construction rather than only in what is said about it. The finished cord is checked by the wearer before use, since a flaw in the weave is considered to compromise its function.

The kusti is not simply worn; it is worked. At the start of each of the five gahs, the watches into which the Zoroastrian religious day is divided, a practicing Zoroastrian performs the Padyab Kusti, a short purification followed by untying and retying the cord while reciting fixed prayers, so the garment is retied as many as five times between dawn and the following dawn. The retying itself carries meaning distinct from the wearing: the untying is understood as casting off the influence of the Hostile Spirit, and the retying as a renewed personal affirmation of the Zoroastrian creed, with specific knots corresponding to specific declarations recited aloud or silently. This makes the kusti one of very few sacred garments anywhere that is ritually manipulated on a fixed daily schedule rather than simply put on once and left.

Investiture with the kusti happens at the Navjote alongside the sudreh, and the two are treated as a single institution in practice even though they are physically separate objects, since neither is considered complete without the other once a person has been invested. Some households mark a child's growth toward the Navjote by having them practice tying a kusti months in advance, so the movements are already familiar by the day of investiture, though this preparatory custom is domestic rather than prescribed by any single authoritative text.