There are lots of reason's Kusatsu is famous for hot springs
Although Japan is famous for hot springs, it’s easy to be tricked into visiting tourist traps where the water is recycled and chlorine added. This is something you definitely won't encounter in all of Kusatsu where the 100 plus gushing springs serve up an astounding 32,000 liters of water minute.
There are two main types of hot spring. Cloudy sulfurous waters that give the town it's distinctive hot spring aroma and clearer, highly acidic waters that are strong enough to dissolve a 1 yen coin in less than a week.
Whichever hotel you stay at in Kusatsu there will almost certainly be a hot spring bath. I like to make full use of the hotel by checking in early (usually from around 2 or 3pm) and taking a quick dip before relaxing in the room or heading back out to explore the town, taking another dip after dinner before bed, and again before breakfast in the morning. Many hotels will have both an indoor and outdoor bath and I almost always spend most of my time in the latter.
The town also has 18 public baths* that are free to enter. These baths feature tiny changing rooms and small tubs that would be full with 5-10 people. Make sure you carry a small towel and wear easy to change clothes and you can take a 5 minute dip in these baths to break your journey and warm up as you stroll around the town. These facilities are primarily there for the local residents rather than visitors so try to go during the day rather than in the evening and be respectful of other bathers by not spending too much time there if it gets crowded.
* A Google map with links to all 21 of Kusatsu's public hot springs
There are also three larger public hot springs with shower facilities and space to relax. They each cost 700 yen or you can get a combined ticket for 1,600 yen for all three. Sai-no-kawara is a huge outdoor pool big enough for 100 hundred people, Goza-no-yu has two baths next to each other each using water from a different source and Otaki-no-yu has a series of baths ranging from 39 to a scalding 46 degrees.
It’s also worth mentioning that Kusatsu’s onsen, while popular for centuries were made even more popular by a German doctor who worked at the imperial palace in the 1800s and who researched the acclaimed health benefits of the springs. He now has a museum in his honor.
Kusatsu is justifiably proud of their hot springs and take the experience to an extreme. After leaving the town you’ll be longing for the energizing and revitalizing waters and wanting to make a trip back. For more on Kusatsu’s onsen check this great guide**.
** The town's own guide to their hot springs
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