Ichinoyu of Kinosaki Onsen is one of the outside hot springs located in the center of the hot spring resort area, and is a renowned hot spring with a long history and tradition dating back to the Edo period. Its name, “Ichi-no-yu,” symbolizes the fact that it was once the center of Kinosaki Onsen. Ichinoyu is also known as the “hot spring of luck,” and along with its beneficial effects, it has been well-liked by many people. Ichinoyu's history is said to date back to the Kamakura period. After the discovery of hot spring water in this area, the area gradually gained a reputation for its efficacy and began to attract visitors for therapeutic hot spring baths. In the Edo period, a hot spring resort was developed, and Kinosaki Onsen became a nationally known attraction. Ichinoyu was one of these hot springs, and it has been loved by both therapeutic bath visitors and tourists. Throughout its history, Ichinoyu has often suffered from disasters, but each time it has been rebuilt by local residents and supporters, leading to its current form. In particular, the building was extensively renovated after a major fire in the early Showa period and damage from Typhoon Muroto in 1934, and now shows a fusion of modern facilities and traditional atmosphere. The building's exterior has a Japanese feel in the shape of its roof and wooden design. At the entrance, a plaque reading “Kaiun-no-yu” (a hot spring that brings good fortune) is hung, giving visitors a sense of good fortune. Ichi-no-yu is said to be good for rheumatism, neuralgia, and muscular pain, and the ingredients of the hot spring are said to have a healing effect on the body and mind. For this reason, Ichinoyu has long been used as a therapeutic bath to improve health, and is now a popular place for tourists to relax. Ichinoyu embodies the charm of Kinosaki Onsen as a whole, and is a place where visitors can feel the depth of the onsen culture and history. Its integrated appearance with the entire hot spring resort is a precious reminder of the good old Japanese hot spring culture.