Onsen

[3] Baths may be either publicly run by a municipality or privately, often connecting to a lodging establishment such as a hotel, ryokan, or minshuku.

Exactly when humans first began bathing in onsen in Japan is unknown, but historical records show it has a history of at least about 1,300 years.

[8] This ancient practice of bathing in onsen to cure illnesses, often for long periods such as a week, is referred to as tōji (湯治).

[8][9] During the Edo period, however, onsen began to gain popularity among the general population thanks in part to depictions of the hot springs in ukiyo-e.[8][9] It is also during this period that the use of onsen shifted from being primarily for religious and healing reasons to being used for bathing for cleanliness and socializing.

[11][12] In modern times, traveling to hot spring resort towns (温泉街, onsen-gai) is a popular form of domestic tourism in Japan.

"[3] Although the number of overnight guests at hot spring resorts has decreased slightly since the boom, travel to such onsen towns as a relaxing getaway is still popular among Japanese people.

[3][12] Traditionally, men and women bathed together at both onsen and sentō communal bathhouses, but gender separation has been enforced at most institutions since the opening of Japan to the West during the Meiji Restoration.

[13] Private onsen called "family baths" (家族風呂, kazokuburo) can be found in many locations throughout Japan.

[22][23][24] The original reason for the tattoo ban was to keep out yakuza and members of other crime gangs who traditionally have elaborate full-body decoration.

[32] A 2014 study conducted in Beppu, a city famous for its onsen, found that regular bathing in onsen has various health benefits such as lowering blood pressure, improving circulation and cardiovascular health, reducing chronic pain and fatigue, and lowering the rate of depression.

[41][42][c] Revelations of poor sanitary practices at some onsen have led to improved regulation by hot-spring communities to maintain their reputation.

[43] There have been reports of infectious disease found in hot bodies of water worldwide, such as various Naegleria species.

[43] These precautions as well as proper onsen usage (i.e. not placing the head underwater, washing thoroughly before entering the bath) greatly reduce any overall risk to bathers.

[21][46][47] In 2021, several people were arrested in connection with an organized group accused of taking photos of women in open-air baths.

A relatively cold bath called mizu-buro (水風呂) is often located directly outside a facility's sauna to allow users to quickly cool down.