On episode 9, Yasaburou and Kaisei went to bath, and they used some kind of citrus fruit like orange and put them inside the bath.
What fruit is this and why did they use it for bath? Does it have any relation with them being a tanuki? When they went to bath before with Akadama-sensei they didn't use this fruit.
It's likely to be yuzu, a sour, tart, graperuit-like citrus fruit that have a very distinctive fragrance. In Japanese cuisine, their juices are often used as seasoning, and their rind as a garnish. It's tradition to a take a hot bath with yuzu during the winter solstice, for the fragrance and various health benefits.
