The term rāga is current not only in the classical traditions of North and South Indian music, where it is the subject of an extensive written and oral theory, but also in many non-classical traditions especially of religious music in South Asia. For example, devotional songs (dāphā) sung by groups of Newar farmers in the Kathmandu Valley, Nepal, are regularly attributed to rāgas; but there is little explicit (i.e. verbally expressed) knowledge about rāga among the performers. The question whether the concept has any musical meaning in terms of melodic structure can only be investigated through comparative musical analysis combined with ethnographic observation. An earlier study (Grandin 1997) concluded that dāphā song melodies in one rāga share a set of characteristic melodic formulae and are thus constructed in a rāga-like way. The present study suggests that rāga-preludes sung before each dāphā song constitute melodic models that underlie song melodies. A common stock of preludes is known by different groups, but singers are not aware of this commonality. There is thus an implicit melodic system that does not depend on performers’ explicit knowledge. This situation can be understood in historical and social terms.