Hakone KAMON

The name “Hakone KAMON” originates from a poem recited by the famous warlord Toyotomi Hideyoshi during the Odawara Campaign of 1590, which marked the end of the Warring States period. The gender-separated large communal baths and open-air baths were designed in the image of the “One-Night Castle” built at that time, giving visitors a taste of the grandeur experienced by the warlord himself. This inn features its own private hot spring source that wells up within the premises. One significant advantage of this is the short distance between the source and the bath, which minimizes the introduction of impurities and the deterioration of water quality due to contact with air.

The spring quality is classified as a Sodium, Calcium - Chloride Sulfate springe, also formerly referred to as a weak salt spring containing gypsum. Indications by Spring Quality unique to this spring include: Cuts, Peripheral circulatory disturbance, Sensitivity to cold, Depression, Dry skin.

The Total Dissolved Substances (excluding gaseous substances) are 2,450 mg/kg, which is about 2.5 times the upper limit of simple hot springs (1,000 mg/kg), indicating a rich and potent therapeutic hot spring. Compared to commercially available bath additives, it contains 16 to 24 times more effective components. Though the water is clear and colorless, it is undeniably a powerful therapeutic hot spring.

First, let’s focus on its weak alkalinity. Human skin is typically slightly acidic. When immersed in a weakly alkaline hot spring, the old keratin on the skin reacts and dissolves, leaving the skin feeling smooth and supple after bathing. This is why alkaline springs are considered a representative type of hot springs for beautiful skin. However, one should be cautious—dissolving old keratin also means the skin can easily dry out post-bath. But no worries with this hot spring. Being a chloride spring in addition to weakly alkaline, the salt in the water forms a film over your skin, almost like a natural body pack, which helps retain moisture after bathing. This effect also slows post-bath perspiration and prevents rapid body heat loss, making it especially effective for those with sensitivity to cold, thus earning the name hot springs for warmth. Additionally, the bactericidal effect of the salt helps soothe various skin conditions, and its effectiveness on cuts and burns gives chloride springs another name—hot springs for cuts.

Another noteworthy feature is its classification as a sulfate spring. This spring promotes skin regeneration by stimulating metabolism, helping to improve skin conditions similar to chloride springs. It’s known to be effective for cuts, burns, acne, psoriasis, itchiness, and chronic eczema. Because of these properties, sulfate springs are also regarded as hot springs for cuts. Moreover, since sulfate springs wash away excess skin oil, they are especially beneficial for oily skin. They also promote oxygen supply to the blood, moisturize the skin, and improve its firmness and hydration—giving them a reputation as hot springs for rejuvenation. Therefore, being a sulfate spring is one of the criteria for hot springs for beautiful skin. Furthermore, the calcium ions in the spring have a calming effect, which is said to help with vascular conditions such as hypertension and arteriosclerosis, earning it the name hot springs for strokes.

Let’s not overlook components not listed in the official spring type. It contains 62.6 mg/kg of metasilicic acid, surpassing the hot spring standard value (50 mg/kg). Known as a natural moisturizing agent, metasilicic acid is even used in some skincare products, contributing to the soft, hydrated feel after bathing. Rich content of metasilicic acid is another hallmark of hot springs for beautiful skin. Also noteworthy is its 46.6 mg/kg of metaboric acid, which is over nine times the hot spring standard (5 mg/kg)—an astonishing amount. Metaboric acid is known for its bacteriostatic and cleansing effects, and it is said to help prevent acne. Some of the open-air baths in the large public bath area, as well as the private open-air baths and rooftop room-attached baths, are free-flowing hot spring baths. The others are maintained with circulation filtration systems that mix fresh spring water with groundwater. A free-flowing hot spring means the water constantly flows into the bath and overflows without recycling—ensuring constant exposure to fresh hot spring water. This is a luxurious style, ideal for those who want to enjoy the full benefits of hot spring components. However, in large communal baths used by many guests, fully free-flowing systems can pose hygiene concerns if bathers neglect proper washing before entry. To maintain cleanliness, these areas mostly use a combined system of 100% natural free-flowing hot spring and circulation filtration, with chlorine disinfection as needed. It's also worth noting that chloride springs and sulfate springs are generally more resistant to quality degradation compared to other types. Despite having only 18 rooms (14 with hot spring baths), the inn offers about 10 different types of baths in the gender-separated large bath and open-air bath areas. Even when fully booked, there’s rarely any crowding. This inn prides itself on offering guests a relaxed and spacious hot spring experience.