“Gensen kakenagashi onsen” refers to a bathing method where hot spring water drawn from a certified source under the hot spring law is continuously poured into the bath, providing fresh water at all times. In this method, the water in the bath overflows and is not recirculated. No circulation or filtration is conducted, preserving the natural properties of the spring. While the original temperature of the spring is generally used, minimal adjustments through slight heating or water addition are permitted to maintain a suitable bathing temperature; however, excessive dilution to compensate for insufficient water volume is not allowed. This method allows bathers to enjoy the full natural benefits of the hot spring.