Abstract: It is necessary for yarn which is wound into packages on supports or centers and is intended to be dyed, or at any rate subsequently employed for other uses, to be able to form, on an annular zone at the sides of the support a number of turns of "reserve" yarn available and intended for joining to the yarn of a subsequent package. In order to fasten the yarn end, a guide notch is formed in the edge of the annular zone and is combined with a portion of very little thickness which can be torn by the yarn which is inserted and forced into the notch such that it becomes wedged in the tear and is held therein. This anchoring device may be provided in either the base or the top of the center, or in both the base and the top of the center, in order to fasten both ends of the wound yarn.