One of my top recommendations for anyone visiting Japan is to visit Koyasan. Koyasan is high in the mountains of the Wakayama prefecture. It is a historically relevant village, considered the centre of Shingon Buddism in Japan. It is here that you can experience a temple stay (Shukubo), many of which include vegetarian haite cuisine and onsen. Guests are welcome to attend early morning meditations. The town and its surrounds are perfect for walks, with the long graveyards nested in forests, large gates, and pilgrimage trails with great views.