As others, not sure if you are thinking of the Kumano Kodo Shinto or Shikoku 88 Buddhist Temple Pilgrimage. I did both and they are very diffferent as explained in this detailed blog post
How The 88 Temple Pilgrimage and Kumano Kodo Are Different From The Camino de Santiago.
The Kumano Kodo pilgrimage routes developed as a way for people to move between the sacred areas on the Kii Peninsula. At the center of this religious area are the three Kumano shrines: Hongu Taisha, Hayatama Taisha and Nachi Taisha, collectively known as Kumano Sanzan. I chose Kohechi because it starts at Mt. Koyasan where at the top is Okonuin Cemetary where the patron saint of the 88 Temple Pilgrimage, Kukai aka Kobo Daishi, is entombed. It also is a 4 day walk through mountain terrain.
Nakahechi is well preserved and relatively easy to walk, leading through hilly, forested landscapes and occasional villages. The section between Takijiri Oji (outside central Tanabe) and
Hongu is about 30 kilometers, and can be done in a comfortable two days’ walk.
Ohechi follows the coast from Tanabe to
Nachi Taisha. This trail has virtually disappeared due to development and the construction of modern roads.
Iseji connects Kumano with
Ise Shrine in Mie Prefecture. Like Ohechi, much of Iseji’s coastal trail has been covered by paved roads and towns. Only short, isolated sections remain as stoned or earthen trails today.
Kohechi connects Kumano with
Koyasan. This mountaintop route is challenging. Inns are rarely found without zigzagging up and down the mountainsides into valley towns, greatly increasing the distance traveled.
Omine Okugake connects Kumano with
Yoshino via Mount Omine. Like Kohechi, Omine Okugake is a difficult route that follows high mountain ridges and barely passes any towns for much of its duration.