おいわけぶし

Etymology
From.

Noun

 * 1) oiwake song, horseman’s song a genre of folk song

Usage notes
Oiwake songs are generally cheerful vocal songs with irregular rhythm, sung with a broad tonal range and often featuring melisma. They are often named for and associated with particular places. See for example (江差追分 Esashi oiwake) on English Wikipedia.