The collective name for the piyyuṭim introduced in the recitation of the morning service on the festivals and on special Sabbaths throughout the year in the Northern rituals (see Zunz, "S. P." passim). These hymns are termed Ḳerobot if intercalated in the repetition of the 'Amidah, but are called in turn "Yoẓer" (creator), "Ofan" (angel), "Me'orah" (light), "Ahabah" (love), "Zulat" (besides), and "Ge'ullah" (redemption) if introduced in the blessings which precede and follow the Shema' at the points where these respective words or subjects occur in the ordinary liturgy. The benediction "Yoẓer" coming first, its title has been extended to cover the whole class of introduced hymns, and, even further, the section of the service itself that centers around the "Shema'" as a whole. The modern tendency is to omit the "Yoẓerot" because their recitation results in excessive prolongation of the services (comp. Ḥazzan and Liturgy).
Owing to the comparative lateness of their adoption into the ritual, there is much less uniformity in the traditional melodies for these piyyuṭim than for any other section of the synagogal melody which dates from before the modern period. The scheme discussed under Ḳerobot is sometimes followed; but more generally the ḥazzan founds his intonation, with much freedom of treatment, on the prayer-motive or model musical interpretation of the particular service in which he is engaged (see Music, Synagogal). When he departs from it, his florid melody is conceived in the spirit of modern instrumental virtuosity (comp. 'Alha-Rishonim) or closely reproduces the old-world folk-song of northerh Europe (comp. Ma'oz Ẓur). But while following the local tradition, he draws a sharp distinction not merely between the jubilant praise of the three festivals and the pleading supplication of the Days of Penitence, but also between the historical reminiscence of the Sabbaths preceding Passover, with their proud reference to the glories of the Temple ritual, and the agonized lament of those coming between Passoverand Pentecost, with their distressful memory of the barbarity of the Crusaders and other persecutors of the dark Middle Ages. This latter sentiment often makes itself felt even amid the joyous melody of the festival days (comp. Beraḥ Dodi).
Whatever may have been the melodies to which such piyyuṭim were chanted when first introduced, the great number of them in the Northern liturgies produced so much inconvenience by lengthening the service that the tunes were soon ignored, and the verses themselves were quickly read through in an undertone, only the concluding stanza being intoned by the ḥazzan (comp. Ḳerobot). In the Sephardic ritual, however, the number of "Yoẓerot" is so small that the originally chosen musical settings, also usually of a folk-song character, have been retained in living tradition till the present (comp. Adonai Beḳol Shofar; 'Et Sha'are Raẓon; Yah Shimeka).