"Totonou"時會發生什麼？為了更加了解這一現像，我們使用MEG（Magnetoencephalography）這一超高精度腦電圖檢測技術，分析了30名體驗者在桑拿前後大腦機能的變化，並觀察到了一個有趣的現像。 除了與人體放松狀態有關的α波被正常化外，在放松過程中常常被抑制的β波僅有位於大腦右側頂葉的一部分會被激活。大腦的右側頂葉負責包括空間和視覺感知、身體感覺與位置信息在內的所有的感官認知。這與桑拿愛好者的反饋是一致的，例如在"Totonou"時腦海中浮現了新的想法，或開始意識到平時沒有察覺到的聲音和氣味等等。此外，β波會因此而減弱。 由於β波的強弱與大腦的興奮程度成反比，因此當我們蒸完桑拿後，會發覺自己變得精神煥發，頭腦也感覺更加清醒。
In the middle of the Muromachi Period (1336 - 1573), a type of tea ceremony in which tea was served to guests after their baths was called rinkan-chanoyu (rinkan sauna and tea ceremony). Much like with shoin-cha (decorative tea time), paintings, incense burners, vases, and hanging scrolls were displayed in the bathing rooms, and it is said that many spectators came to watch toucha (tea-tasting games) after bathing.
Rinkan-chanoyu was a widely-practiced basara (eccentric hobby) in Japan, particularly at the Kofukuji Temple in Nara.
In those days, a bath was a steam bath, or what we would today call a sauna, in which water is poured over heated sauna stones. People in Japan have long enjoyed the acts of viewing art in a sauna and drinking tea as a cultural pastime.
The term basara refers to the social and cultural trends in the middle ages in Japan, mainly during the early Muromachi Period (the Nanboku-cho Period). It was an aesthetic of meritocracy, one that disregarded the status quo, belittled, ridiculed, and rebelled against the authority of those noble in name alone, and instead favored extravagance, flamboyant behavior, and chic clothing. This culture was also the seed of the later revolutions in the Warring States Period.
It is said that Murata Juko (1422 - 1502), the teacher’s teacher of Sen no Rikyu (1522 - 1591) and the inventor of wabi-cha (tea ceremony), was also enamored with rinkan-chanoyu when he was young. He later studied under the Japanese monk Sosun Ikkyu at Daitokuji Temple, reached a state of chazenichimi (the realization that tea ceremony and Zen are one), and created wabi-cha. Then, the brothers Furuichi Choei and Furuichi Choin, who were main figures of rinkan-chanoyu, became disciples of Murata Juko, and rinkan-chanoyu became wabi-cha.
2008年前後，桑拿愛好者開始在SNS（社交網絡）上進行信息的傳播和交流，2009年，漫畫家タナカカツキ（Tanaka Katsuki）開始了《サ道（桑拿之道）》文章的連載，首次通過漫畫的形式，將進行“熱水浴”、"冷水浴"、"休憩"的反復為人體帶來"Totonou"的特殊狀態的過程與方法進行了可視化。（ 2011年《サ道（桑拿之道）》文字版發行時，將"Totonou"稱為"Sauna Trance"）。 桑拿愛好者濡れ頭巾ちゃん（Nure zukin-chan）在2011年開通博客時發表的評論"Totonou！"使"Totonou"一詞在以SNS（社交網絡）為中心的桑拿愛好者中開始逐漸流行起來。 2015年《漫畫版 サ道（桑拿之道）》連載開始時，采用了"Totonou"的用法，"Totonou"由此正式傳播開來。
*衷心感謝田タナカカツキ（Tanaka Katsuki）及濡れ頭巾ちゃん（Nure zukin-chan）為本文的撰寫提出的寶貴建議。
Inference of Connection of Sauna Trance with Japan's Infrastructure and Cultural: Public Baths and Water Baths
When did the sauna trance method of bathing, which has been implicitly inherited by sauna lovers, begin?
The Japanese steam bath was replaced by the modern bathing in hot water baths in the mid-Edo period (early 17th century). The modern sauna was introduced to Japan from Finland around the time of the 1964 Tokyo Olympics. In Finland, there are many lakes, and in saunas near lakes people do jump into the cold lakes, however, saunas in the city do not always have cold water baths.
So when did saunas in Japan start to always include a water bath? In fact, it is believed that water baths existed in public baths long before saunas. If you were born in the countryside in Japan, you may have been told by your grandfather to "pour cold water over yourself" at the end of a bath.
The story of pouring cold water over yourself after a steam bath appears in the collection of medical essays by the court physician of the late Kamakura period (late 13th century), Tomotoshi Koremune, in his book "Idansho" (one of the oldest essays by a physician in Japan). Since the days of the steam bath, cold water has been poured over the body after a steam bath. This may have something to do with misogi, the ancient Japanese Shinto ritual of purifying oneself by bathing in waterfalls and rivers. Even today, this is done at shrines at its chozu-ya pavilion which contains a large water-filled basin. Since the Nara period (8th century), when public baths were built, people have been pouring cold water over themselves after steaming baths. At the very least, the alms baths created in the Nara period were replaced by hot water and remained in the city as public baths called sento, and the pouring of cold water over oneself was somehow replaced with water baths. The practice of alternating hot and cold baths may have been implicit for more than a thousand years. This may have been the infrastructure and cultural foundation that led to the development of totonou (sauna trance) brought about by alternating super hot and cold baths.
Reference (Japanese): Sento kentei koushiki text 1
(Reference) Gyoki and the Origins of Japanese Baths (Saunas) teamLab Ruins and Heritage: Rinkan Spa & Tea Ceremony