Tateshina Ai is an exclusive inn in the highland thermal retreat of Tateshina. While staying for the night is certainly recommended, you also have the possibility of dining at their restaurant as a visitor.
Their Japanese traditional course meal features many typical ingredients of this mountainous region, including wild herbs in spring, highland vegetables in summer, and mushrooms in autumn.
If the whole spread is a little too much for you, at lunch you can order their informal mini-course meal, which is less voluminous but just as luscious.