Naguri Onsen Taishoukaku is a historic hot spring ryokan nestled in the mountains of Shimonaguri, Hanno City, Saitama Prefecture. Founded in 1914 (Taisho 3), this venerable inn has served guests for over a century, offering a tranquil retreat surrounded by the lush nature of the Naguri Valley, despite being only about one hour from central Tokyo. The source spring is known as Naguri Radium Mineral Spring, and has long been cherished by locals as a therapeutic bathing destination.

The water is classified as a hypotonic alkaline cold mineral spring with a source temperature of approximately 7 degrees Celsius. It has a pH of 8.5, indicating alkaline properties, and meets hot spring legal standards with 1.9mg of total sulfur content. The total mineral content is a mild 174mg, producing characteristically soft water that is gentle on the skin. In addition to heated baths adjusted to around 40 degrees Celsius, a cold plunge bath using the 7-degree source water is also available.

The panoramic public baths are located on the top fifth floor, offering sweeping views of the Naguri countryside. The facility boasts seven different bathing experiences: the Kengyu-no-Yu (men) and Orihime-no-Yu (women) main baths, the Amanogawa (men) and Ginga (women) open-air baths, a rotating Ki-buro wooden bath, and two private baths called Tsuchi-buro and Iwa-buro. Day-trip bathing is available for 1,600 yen for adults from 11:00 to 15:00. The inn has 19 guest rooms and features local touches throughout, including wooden pillows crafted from Nishikawa cedar.