A pot six meters across. On the dry riverbed of the Mamigasaki in Yamagata, every September, they cook what they call the greatest imoni in Japan: three tons of taro and a ton of beef tipped into an enormous iron cauldron, the ingredients loaded by machine, the fire fed with split wood. A crane stirs it, because no ladle could. Imoni itself is nothing grand. It is the ordinary autumn ritual of the region—families and coworkers gathering on a riverbank, building a fire, sharing a pot of taro stew. Inland Yamagata makes it with soy sauce and beef, and will argue the point with anyone who makes it otherwise. The festival is simply that same homely act, scaled past reason: some thirty thousand servings cooked and gone by the end of a single day. It is not a spectacle in the usual sense. No floats, no fireworks. People come to a riverbed to boil potatoes. But thirty thousand of them come, to boil potatoes together, and watching the steam rise off that absurd and serious pot, you begin to understand what autumn means here.