Mount Iizuna, also known as Mount Iizunayama, is a beautiful mountain in the northern part of Nagano Prefecture. Rising to an elevation of 1,917 meters, it stretches across Nagano City, Shinano Town, and Iizuna Town. The mountain is popular with hikers, mountain enthusiasts, and travelers seeking to experience the natural beauty of the Nagano region.
The name Mount Iizuna can also refer collectively to a mountain range that includes its subsidiary peaks, such as Mount Reisenji at 1,875 meters and Mount Menou at 1,748 meters. Together with Mount Togakushi, Mount Kurohime, Mount Myoko, and Mount Madarao, Mount Iizuna forms one of the Five Mountains of Northern Shinano, known as the Hokushin Gogaku. These mountains have long been important symbols of the region.
Mount Iizuna is a stratovolcano belonging to the Myoko volcanic group. It is a double volcano whose activity is believed to have begun approximately 250,000 years ago and continued until around 50,000 years ago.
Volcanic deposits produced particularly between approximately 150,000 and 125,000 years ago are known as the Iizuna Uwadaru Tephra and Iizuna Nishiyama Tephra. These deposits have been identified far from the mountain, including around the Konandai Plateau near Kumagaya in Saitama Prefecture and the Shirakura area of Kanra Town in Gunma Prefecture.
Because these layers can be identified over a wide area and correspond to particular periods in geological history, they are valuable reference materials for understanding the development of the surrounding landscape.
The slopes of Mount Iizuna provide opportunities for outdoor activities throughout the year. The Iizuna Kogen Ski Area extends across the southern slopes, while Iizuna Resort Ski Area lies on the eastern side. On the western slopes of Mount Menou, which forms part of the Mount Reisenji range, visitors can also enjoy Togakushi Ski Resort.
During winter, the surrounding mountains become a popular destination for skiing and other snow sports. In warmer seasons, hiking and nature walks offer a completely different experience, with fresh greenery in spring and summer and brilliant autumn foliage later in the year.
The area around Mount Iizuna is dotted with scenic places where visitors can enjoy the changing seasons. These include Lake Iizuna, Lake Ozahoshi, Lake Reisenji, Sakaidani Wetland, and Mure Onsen Tengu-no-Yu.
Together, these attractions make the Mount Iizuna area an appealing destination throughout the year. Summer is ideal for hiking and walking in the highlands, autumn brings colorful foliage, and winter transforms the mountains into a playground for snow sports.
Mount Iizuna has been revered as a sacred mountain for centuries. It became an important center of mountain worship and Shugendo, a Japanese religious tradition combining Buddhist practices, mountain asceticism, and elements of local belief.
The mountain was associated with the worship of Iizuna Gongen and attracted the devotion of powerful historical figures. The Hosokawa clan, Uesugi Kenshin, Takeda Shingen, and Tokugawa Ieyasu are all traditionally associated with reverence for the mountain and its deity.
Along the hiking trail, visitors can encounter 13 stone Buddhist statues, including images of Fudo Myoo, the Buddhist deity known as Acala. These statues form part of the mountain’s religious landscape and recall the days when climbing the mountain was also an act of pilgrimage.
The worship of Mount Iizuna gave rise to the distinctive religious figure known as Iizuna Gongen. As a deity reflecting Japan’s historic tradition of combining Buddhist and Shinto beliefs, Iizuna Gongen is traditionally depicted as a fierce figure riding a white fox, with the appearance of a Karasu Tengu, a crow-like mountain spirit, while carrying a sword and a sacred rope.
Iizuna Gongen became particularly associated with military success and was revered by members of the samurai class. Uesugi Kenshin is famously associated with the deity and is traditionally said to have displayed an image of Iizuna Gongen on his helmet.
The deity also came to be worshipped in connection with agriculture and protection against fire, allowing the faith to spread well beyond the mountains of Shinano.
The religious tradition surrounding Iizuna Gongen also developed a more mysterious side. The practice known as Iizuna-ho, said to have been transmitted through the deity, was regarded by some people during the medieval and early modern periods as a form of occult or forbidden practice.
It was associated in folk belief with the supernatural control of tengu and foxes. Various legends developed around these practices, including the belief that burning shikimi incense could prevent the power of Iizuna-ho from taking effect.
Although such beliefs belong largely to the world of traditional folklore, devotion to Iizuna Gongen continues today in Shinano and elsewhere in eastern and northern Japan, including at Yakuoin Temple on Mount Takao in Tokyo and Kanozan Jinya Temple in Chiba Prefecture.
At the summit of Mount Iizuna stands Iizuna Shrine, regarded as the head shrine of the many Iizuna shrines found throughout Japan. It formerly held the status of a village shrine under Japan’s prewar shrine ranking system.
The shrine’s origins are traditionally traced back to around 270 CE, when Tenjin Otochinomikoto was said to have been enshrined on the mountain. In 848, the ascetic Gakumon Gyōja is said to have entered the mountain, while in 1233 the local land steward Ito Tadatsuna reportedly rebuilt the shrine after receiving a divine revelation.
Tadatsuna’s son, Moritsuna, is said to have inherited the practice of Iizuna-ho, eventually becoming associated in tradition with the origins of ninjutsu. The shrine’s Buddhist counterpart is traditionally identified as Mahavairocana Buddha, reflecting the mountain’s long history of Buddhist-Shinto syncretism.
The name Iizuna is traditionally linked to iizuna, a name associated with a mysterious substance once found in parts of Shinano. It is said to have been a colony of microorganisms known as Tengu no Mugimeshi, literally “tengu’s barley rice.” According to local tradition, it once existed in the mountains around Iizuna but is now believed to have disappeared.
Legends tell of tengu distributing this mysterious “food” to people suffering from hunger. Such stories helped give the mountain and surrounding place names a distinctive connection with the supernatural world of Japanese mountain folklore.
Iizuna Kogen is a highland resort where visitors can enjoy nature in every season. Its refreshing mountain air makes it an excellent place for forest walks, picnics, and relaxed outdoor activities.
Lake Ozahoshi is a historic pond created in the early Edo period. A walk around the water offers peaceful scenery and a chance to enjoy the quiet atmosphere of the highlands.
Lake Reisenji is a tranquil mountain lake surrounded by nature. Visitors can enjoy activities such as boating and fishing while taking in the changing scenery throughout the year.
Mure Onsen Tengu-no-Yu is a natural hot spring facility where hikers and outdoor enthusiasts can relax after a day in the mountains. The outdoor bath provides views toward Mount Iizuna, making it an especially pleasant place to unwind.
Sakaidani Wetland is a valuable highland wetland that has existed for approximately 100,000 years. It provides habitat for a variety of rare plants and insects and is an excellent destination for nature observation.
Mount Iizuna is much more than a hiking destination. Its volcanic origins, highland landscapes, ski resorts, lakes, and wetlands reveal the natural history of northern Nagano, while its ancient mountain worship and legends of Iizuna Gongen reveal another layer of the region’s cultural heritage.
For travelers interested in both nature and Japanese spirituality, the mountain offers a fascinating journey through landscapes shaped by volcanoes and beliefs shaped by centuries of pilgrimage. From the surrounding highlands to the summit shrine, Mount Iizuna provides a memorable way to experience the natural and spiritual character of Shinano.