Onsen Tradition in Kusatsu

One of the oldest and most reputed onsens in Japan, Kusatsu was a favourite of the 5th and 8th shoguns ( it’s said that they transported waters to their castle in Edo). The onsen, while being preferred by Japanese for more than 1000 years, is relegated to a paragraph at best in the leading English language guidebooks and travel magazines

It was Dr. Erwin von Baelz, who brought some international renown to the area. In 1896, Dr Baelz, a German physician and university lecturer, presented his findings on the unique nature of the Kusatsu spring water to the medical community. The chemical properties of the water- traces of iron, aluminium and arsenic and a ph of 2.1, led Dr. Baelz to believe that it could completely cure any disease as few bacteria/ germs could survive such a level of acidity. Dr. Baelz discovered that a caldera lake (yugama) at the summit of Mt. Shirane was the source for the onsens in Kusatsu.This lake water still filters through the mountain then through to yubatake - literally meaning field of hot water- at 55 degrees celsius ( 131 degrees Farenheit).
Kusatsu is blessed with the highest volume and highest temperature in Japan, all natural.

Yubatake is really the heart of Kusatsu. Located in the centre of town, it is a series of natural cooling filters -wooden aqueducts- where the fiery hot spring water is first cooled. It is a gathering point for water and for people, and it is where visitors, vapours and bright yellow sulphur deposits intermingle. The water is then distributed to the town and is further cooled by the yumomi process- a traditional rhythmic stirring of the water in the onsens.
Yubatake is the start of life for the town- its onsens, footbaths, and sentos. It is surrounded by restaurants, and galleries. Narrow streets, like arteries, branch off in diverse direction offering more opportunities to explore of the town.