Kol Nidre is the opening Yom Kippur chant that concerns the annulment of vows.
It is recited before nightfall at the beginning of the Yom Kippur evening service. The Aramaic formula asks that certain personal vows and obligations made during the coming year be declared void under specified conditions. The text has a complicated history, and its exact legal meaning has been interpreted differently by Jewish authorities.
Kol Nidre is not itself a general cancellation of promises made to other people. Its subject is religious vows and obligations covered by the formula, not ordinary contracts or debts. This distinction is important because the chant is sometimes inaccurately described as permitting people to break any promise.
The melody is among the most recognizable in Jewish liturgy. In many communities, the Torah scrolls are brought out while Kol Nidre is sung, giving the service a particularly solemn opening.