Along the way, walkers encounter about 100 "oji" (subsidiary shrines of Kumano Sanzan), at which Japanese pilgrims stop and offer prayers.
The oji's purpose is to enshrine natural landmarks in the area -- be it an ancient tree or a majestic waterfall.
Here's the routine: drop a coin in the donation box in front of the shrine, ring the bell above the box, bow twice and clap twice, pray then bow once more. Got it?
"Any coin is fine, but the most common is the five-yen coin, called 'goen' in Japanese," says Brad Towle, director of Tanabe City's international tourism promotion and development department.
"It means 'good relationship' and offers hopes for a bonding with God."
Where to start
Among the seven major Kumano Kodo routes, Nakahechi, which stretches from Tanabe City in the west to Shingu in the east, is the most popular and what we are focusing on here.
Local buses run from Tanabe City's KiiTanabe train station to Takijiri-oji, the entrance of Kumano Kodo and beginning of the Nakahechi route. (Check out the "Getting around" section at the end of this article for the link to an English-language bus schedule.)
Here you'll find an information center offering details on the route, as well as free bamboo hiking sticks and a booklet to fill with stamps from various landmarks along the hike.
Bamboo stick in hand and five-yen coins in pocket, Kumano Kodo hikers usually reach the Chikatsuyu-oji mini shrine in Nakahechi on the first day. It's about 16 kilometers from the Takijiri-oji entrance and takes about six hours of walking.
The following day is a whopper -- hikers trek 26 kilometers from Chikatsuyu-oji to reach Kumano Hongu Taisha, the first main shrine on this route.
Kumano Hongu Taisha was relocated to its current location from Oyunohara after being salvaged from floods in 1889.
There's a large exhibition hall and information center nearby with an interesting mix of details on the pilgrimage.
Most pilgrims then take the 90-minute boat ride from Hongu down the Kumano-gawa river to Kumano Hayatama Taisha and Kamikura Shrine in Shingu -- the one with all those steps.
(Click on the map above for an enlarged look at all the routes.)
Hayatama Taisha enshrines a beautiful 800-year-old nagi tree; Kamikura Shrine pays tribute to a gigantic rock, Gotobiki-iwa, on top of Gongen Mountain.
Before heading to the last grand shrine of Kumano Nachi Taisha and the stunning Nachi Falls, pilgrims enjoy one of the easiest walks of the journey, which starts from Daimonzaka. (To get there, visitors can hop on one of the regular buses that pass through Shingu and get off at Daimonzaka.) This section of the hike is on a gentle slope made up of cobblestone stairs lined on both sides with gorgeous Japanese cedars.
Scenery aside, it's a great place to take in some old school cosplay action. Plenty of pilgrims head for Daimonzaka and change into traditional Heian-era kimonos from the 8th century.
"We dress up in these old kimonos once a month and walk to Kumano Nachi Taisha," a 27-year-old walker from Osaka named Sanae Takano told me as we shared a stretch of trail.
"It's the fourth time we've visited the Nachi Taisha in traditional kimonos," added her companion, Toshifumi Kurinobu. "It's how the earliest pilgrims traveled in ancient times."
Heian kimonos can be rented at the Daimonzaka Chaya teahouse by hikers who want to dress the part.
Best short route: Hosshinmon-oji to Kumano Hongu Taisha
Another easy walk is the Hosshinmon-oji to Kumano Hongu Taisha route. (See the green line on the map.)
"This walk takes about two hours through forests and farming communities," says Towle, of Tanabe City's international tourism promotion and development department. "It ends at Hongu Taisha, the grand shrine."
When I walked the route, I stopped at the Fushiogami-oji Chaya (tea shop), which is run by a group of volunteers of a local women's association.