At an elevation of 885 meters, deep within the Ubako forest of Hakone, Shumeikan is a day-use hot spring facility housed in a Taisho-era building. Ubako Onsen is one of the historic Hakone Seven Hot Springs, renowned for its connection to the legend of Kintaro (the Golden Boy). According to the tale, Kintaro's mother, the mountain witch Yamauba, healed his injured eyes with this spring water on the advice of the Hakone Gongen deity — earning Ubako its place among Japan's "Three Great Eye-Healing Hot Springs." The facility's most remarkable feature is its natural foot-source spring, where hot water wells up directly through the bottom of the bathtub, delivered without any dilution, heating, or chemical treatment. With only about 15 visitors per day, the profound silence, combined with the Taisho-era wooden architecture and crisp acidic spring water, has earned Shumeikan the highest praise from hot spring connoisseurs as perhaps the most authentic hot spring experience in all of Hakone. The facility does not advertise, does not serve food — it exists purely as a place to commune with the water.