The Saigoku circuit's own account of its origin runs like this. Tokudo Shonin, a monk of Hasedera, was said to have died, met Enma, the judge of the dead, and been sent back with instructions to establish thirty three places of Kannon so that people might avoid hell, together with thirty three seals to authenticate them. The pilgrimage he founded then lapsed, and was revived in the late tenth century by the retired emperor Kazan, who had taken monastic vows after a short and unhappy reign and who is credited with fixing the order of the temples and walking it himself.
Whatever the history behind the legend, the effect is documented: from the medieval period the Saigoku route was the established pilgrimage of central Japan, walked by aristocrats, then by warriors, then, once Edo period road travel made it possible, by ordinary people in organised confraternities.
Its structural importance is that it invented the form. A numbered circuit of temples sharing a single dedication, with a fixed order, a stamp book and a set of pilgrim songs, is now the standard shape of Japanese pilgrimage, and several hundred circuits use it. The Bando thirty three in the east and the Chichibu thirty four were established in imitation, and completing all three, one hundred temples in total, is a recognised achievement in its own right.
The goeika, the pilgrim songs assigned one to each temple, are sung at the hall on arrival and are the audible marker of the tradition.
The circuit runs from Seiganto ji beside the Nachi waterfall, which is also a Kumano site, to Kegon ji in Gifu, and takes in Kiyomizudera, Ishiyamadera and Hasedera among others.