Mt. Gassan, Mt. Haguro and Mt. Yudono, collectively known as the Dewa Sanzan (Three Sacred Mountains of Dewa), are located in central Yamagata Prefecture. The Dewa Sanzan mountains boast of having the oldest history of mountain worship in Japan, where ascetic devotees called Yamabushi (mountain priests) pay reverence, and even today wear the traditional white robes and diadem.

Haguro San
Part of Dewa Sanzan's appeal is its remoteness. Yamagata’s heavy snowfall makes travel in the mountains difficult during the winter months when only Mt. Haguro remains open. The best time to visit is between July and mid September when all three mountains are open to pilgrims and tourists.
 
Mt. Haguro-san is 414 metres high and surrounded by a dense cedar forest that starts at the Zuishin Gate. There are 2,446 stone steps that lead to the mountain top. Beyond this dark, shaded stairway, you can see a striking five-story pagoda that rises up towards the sky, one of Japan's National Treasures. Sanjingo-saiden Shrine, which enshrines gods of all three sacred mountains, sits near the top of Mt. Haguro. It has a 2.1-metre-thick thatched roof, and the interior is completely covered with Japanese lacquer, a sight that is well worth seeing.
 
The top of Mt. Gassan lies at an altitude of 1,984 metres. There you will find Gassan Shrine, with its excellent view, as well as the famous Mida Marsh where you can enjoy yellow alpine lilies, black lilies, Japanese skunk cabbage) and other marsh vegetation.
 
At an altitude of 1,504 meters is Mt. Yudono, deemed the ultimate ascetic disciplinary practice ground. Yudono Shrine is revered as hallowed land which must be kept secret. It is a highly mysterious shrine and photography and video recording are still prohibited today.
 
Access: From Tokyo: 2hrs to Niigata Station by JR Joetsu Shinkansen Line, and 1hr 50 mins from Niigata to Tsuruoka Station by JR Uetsu Line (limited express). 60mins from Tsuruoka Station to the top of Mt. Haguro by bus, or 1hr 45mins from Tsuruoka Station to the Hachigome bus stop at Mt. Gassan by bus (only in summer).
 
Further information: The Three Sacred Mountains of Dewa