Three Mountains of Dewa - Credit: Wikimedia Commons
The refer to the three sacred mountains of Mount Haguro, Mount Gassan and Mount Yudono, which are clustered together in the ancient province of Dewa (modern-day Yamagata Prefecture). Holy to the Japanese Shinto religion and especially the mountain ascetic cult of Shugendo, Dewa Sanzan are a popular pilgrimage site visited by many, including famed haiku poet Matsuo BashÅ. Read more on Wikipedia
Source: en.wikipedia.org