Imoni

Imoni is a type of taro and meat soup eaten traditionally in the autumn in the Tōhoku region of Japan. Yamagata Prefecture in particular is famous for its imoni, but other prefectures in the region also have their own different varieties. Imoni is eaten like any soup, primarily during the late summer and early autumn, but is most famous as an outdoor food. In the autumn, groups of people preparing imoni around a fire near a river is considered a sign of the season, and convenience stores maintain a stock of firewood and other supplies just for the occasion. The different recipes for imoni vary from prefecture to prefecture: for example, inland Yamagata imoni contains beef, sugar, and soy sauce and is sweet, while the imoni prepared in the neighbouring prefecture of Miyagi does not, but includes miso paste to flavour the soup. Similarly, even the Shōnai region of Yamagata features a pork and miso base rather than the beef and soy sauce base of inland areas of the same prefecture. However, several ingredients are considered standard parts of the recipe:

Source: Wikipedia