Miyaza is the empowered group in a village or its qualified members engaged in rituals of a shrine, a guardian god or a local deity of a village. As it had no full-time Shinto priest, members of Miyaza took the role of Shinto priest on a yearly rotation, which was called the Toya system (a person- or family-on-duty system).
The word 'Miyaza' came into being after the early-modern times, especially in the areas around Western Japan (in Eastern Japan, a designated 'Sohonke' [main branch of a school or religion] mainly took in charge); however, the origin of the group was traced back to the end of the ancient times. So, regardless of the presence or absence of the word 'Miyaza,' the group consisting of village inhabitants without the status of Shinto priest, which conducted rituals, was called 'Miyaza' in the field of academic research such as history, folklore, and religious studies.
Miyaza roughly consisted of two groups: Kabuza (a closed group) and Muraza (an open group). Kabuza was the privileged festival group, in which only designated family members with qualifications for membership over generations such as Nanushi (village headman), Kusawake (a pioneer), Kanjoshu (a person who prays for the coming of a deity), Shake (family of Shinto priests serving a shrine on a hereditary basis), Shanin (Shinto priesthood of a lower rank) and their related families could participate. On the other hand, Muraza was a festival group in which any village inhabitant who had reached a certain age or finished Genpuku (a coming-of-age ceremony) could participate; even though the group had a quota of fixed members, they were allowed to enter the group in order of age or ceremonial conferment when a vacancy becomes available. According to one popular theory, Kabuza was established first, and then liberated to become Muraza; the opposite view is that Muraza was terminated by stratification and became Kabuza. Miyaza having a multilayered structure in which Kabuza coexisted with Muraza was also found in and around the capital. Basically, Miyaza adopted the Roji system; members were divided into Wakashu (younger members), Churo (people around the age 50), and Otona or Toshiyori (leader of a village) in order of age and experience; in Otona, there were ranks from Ichiro (ichi osho), the general manager, to Niro (ni osho) and Sanro (san osho). There were two ways to assume the post of Shinto priest who performed rituals; Ichiro took the position; members of Otona did on a yearly rotation (Ichinen Kannushi, Nenban Kannushi). Toya or Tonin (heads) who had the responsibility for the preparation of rituals was decided in order of age, family status, or admittance to Miyaza and by drawing lots (Sometimes, Shinto priest served concurrently as Toya). The role of Toya was generally performed by one family; however, related families or neighbors occasionally helped it; the former was called Honto, and the latter were called Wakito, or Sukekashira. The special rice fields called Kuden or Zaden were established and used for operating Miyaza, and for Shinsen (food and alcohol offering to the gods) in the rituals; Toya gave a special treatment to those rice fields by cultivating them without using dung for fertilizer to achieve purity. Miyaza also held forest lands, whose profits were used for its operation.
After the war, the academic research on Miyaza developed rapidly. The prominent researchers are Kazuo HIGO, Takeshi TOYODA, Toshiaki HARADA, Narimitsu MATSUDAIRA, Tatsuo HAGIWARA, Seiichi ANDO, and Toshiki SONOBE.
It is very difficult to clarify the origin of Miyaza; one theory holds that Miyaza was related to the establishment of Za, a type of monopolistic trade association of medieval Japan. 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. In such a group, vertical relationships were developed according to the roles of ritual services or positions within the group; people inside the village were even excluded, much less people outside the village because the positions within the group were limited. After Soson (a community consisting of peasants' self-governing association) was established, the regional characteristics of the group were enhanced; Miyaza was extensively present in the 15th century, and sometimes, the system of Miyaza was directly reflected in the operation of Soson.
In the Edo period, Murakiri (defining boundaries of a village) was conducted under the shogunate system, and the Honbyakusho (a freeholding farmer) system was established; Miyaza (zakata) and the village administration (murakata) were operated separately. As the Roji system weakened, the group's hierarchy was permanently determined by family status. However, with its rebound, when the Honbyakusho system was abolished in the late Edo period, a series of disputes broke out: Zanami disputes concerning the positions within Miyaza and Kanyu disputes concerning membership for villagers who were excluded from Miyaza. In the following Meiji Government, the separation of Buddhism and Shintoism, land-tax reform, and the introduction of state-Shintoism transformed the structure of Miyaza; the postwar democratization and agrarian reform gave an additional blow. The most severe blows were the urbanization during the high economic growth period as well as the progress of the depopulation and aging in rural areas. Under these circumstances, there are a few people who preserve Miyaza, an exclusive and closed group including Kabuza; however, some are changed to Muraza or broken up, and the increasing number of others are transformed into new organizations such as 'a preservation society' of local performing arts or traditional folk entertainments.