ONSEN

Natural hot springs (温泉, onsen) are numerous and highly popular across Japan. There are many types of hot springs, distinguished by the minerals dissolved in the water. Different minerals provide different health benefits, and all hot springs are supposed to have a relaxing effect on your body and mind. Hot spring baths come in many varieties, indoors and outdoors, traditional and modern. 
Tauck's tour has no opportunity to participate in a hot springs. Passengers can visit a spa in the hotel or nearby.
In Osaka, 

Conrad has its own SPA. There is also a  SpaWorld (4.5 miles away) The Spa World has an Onsen with separated by gender so no swimsuits and towels are allowed in the Onsen. However, the Spa pools & Bade Zone area on 8 will be mixed-gender so swimwear is required.