Hot Spring Water and Its Traditional Benefits
Characteristics of the Spring
The waters of Shiriyaki Onsen are classified as a chloride spring. Such springs are traditionally valued for their warming properties, helping the body stay warm after bathing. The water has also traditionally been associated with soothing various skin conditions and minor cuts.
The History of Shiriyaki Onsen
A Hot Spring with Ancient Origins
Shiriyaki Onsen has a long history and is traditionally said to have been discovered by people fleeing the defeat of the Heike clan. Although the exact date of its discovery is unknown, the hot spring already appeared on maps dating from the Kaiei era (1848–1854), suggesting that it had been known as a hot spring destination for many years.
The Origin of the Name “Shiriyaki”
The name Shiriyaki, literally meaning “burning the buttocks,” is said to come from the way the hot spring naturally emerged from the riverbed. People would sit on warm stones heated by the spring water in an attempt to soothe hemorrhoids and other discomforts. This unusual practice is believed to have given the hot spring its distinctive name.
The Hot Spring Area and Its Facilities
Kawa-no-Yu: A Natural Open-Air River Bath
The most famous attraction at Shiriyaki Onsen is Kawa-no-Yu, located along the Nagasasa River, a tributary of the Shirasuna River, which itself flows into the Agatsuma River. Hot spring water naturally emerges from the riverbed, and part of the river has been dammed to create a vast open-air bathing area.
The natural bath is so large that it resembles a swimming pool, creating an exceptionally unusual onsen experience. Bathers can enjoy the warm water while surrounded by the forests and mountains of the area.
How to Enjoy the River Bath
A small bathing hut is located beside Kawa-no-Yu. Swimsuits are not permitted in the bathing hut. The larger outdoor section formed by damming the river has no dedicated changing facilities. Some visitors therefore wear swimsuits, while many others bathe nude, as is customary at Japanese hot springs.
However, conditions in the river can change rapidly. During periods of heavy rain, snowmelt, or sudden rainstorms upstream, the river may become a strong current, making bathing in the river impossible. Visitors should always check the conditions before entering the water and exercise caution.
Shiriyaki Onsen Benten-no-Yu
On December 19, 2023, the town opened a new public day-use hot spring facility, Shiriyaki Onsen Benten-no-Yu, on the former site of Iriyama Elementary School.
The facility took over the functions of Bade Kuni, which had previously operated inside the Kuni Onsen Medical Center. The hot spring water is supplied to the new facility from the former center. With the opening of Benten-no-Yu, Bade Kuni was closed, providing visitors with a new place to enjoy the waters of Shiriyaki Onsen.
A Unique Hot Spring Destination Surrounded by Nature
Shiriyaki Onsen offers an unforgettable combination of nature and hot springs. Its famous Kawa-no-Yu transforms a mountain river into a vast natural bath, while the newer Benten-no-Yu provides a more conventional day-use bathing experience.
Surrounded by the mountains of Nakanojo, this secluded hot spring offers a chance to experience a very different side of Japan’s onsen culture. Whether enjoying the remarkable river bath or relaxing at the modern facility, visitors can take time to unwind in a peaceful natural setting steeped in history.