The Japanese soup imoni is a popular seasonal focal point at social events all over this island nation. Literally translating to "simmering potatoes," this soup typically uses the native taro style of potato with beef and a range of Asian-centric seasonings and vegetables. In the Japanese city of Yamagata, the annual Imoni Festival is the largest in the world, with a giant batch of the soup prepared downtown in a vat nearly 20 feet (about 6 m) in diameter.
This soup is primarily served in the fall, during the September harvest for taro potatoes. Thought to be one of the first cultivated vegetables, this plant has a starch-rich tuber, or corm, at its base, but is widely recognized for its elephant ear leaves. Taro is grown throughout the world in 2011, mostly for landscaping as it is only a regular staple in Asia and Africa.
After peeling the taro potatoes, and cutting them into large chunks, chefs will cook some chopped onions and strips of beef in an oiled pan. Soy sauce and sugar are added for flavor, then the taro chunks go in, along with enough water to submerge everything in the pot. Another Japanese delicacy, called konnyaku, or devil's tongue, adds a slimy, noodle-like consistency with very few calories. Just before the potatoes are cooked through, salt, pepper and monosodium glutamate are regularly added to balance out the flavors.
A range of imoni variations are available. Often, different Japanese cities will have slightly different imoni recipes. Hard-boiled eggs, wild mushrooms, cabbage, daikon, carrots, beets, snow peas or celery can be added for more color and texture. The taste can be elevated even further by adding seasonings like curry or chile powder, or even a few belts of sake. Miso paste is regularly substituted for or added to the soy sauce component.
When imoni forms the center of a social gathering, the celebration is called an imonikai. At Yamagata's autumn festival, ingredients are added to the giant pot with a mechanized crane. To feed about 30,000 attendees every year, the city's appointed chefs must assemble a soup with nearly 3 tons (about 2,250 kg) of taro potatoes, 1.2 tons (nearly 1,100 kg) of beef, 3,500 onions, 185 gallons (or 700 liters) of soy sauce and equally heavy portions of all the other ingredients.