The most convincing theory is that Miyaza originated in the Banyaku or Toyaku system in the late Heian period (the 11th century) in which a lord of the manor or a officer governing manors allotted the roles of ritual services to powerful local figures.
有力説としては平安時代後期（11世紀）に荘園領主や荘官が在地の有力者に神事の役割を負担させた番役制・頭役制に由来すると言われている。