Fermented foods are time-tested aliments full of Umami. The Central Japan area, being the center of action in Medieval Japan, offers two fine examples of such traditional food; Hatcho Miso and Heshiko.
In Okazaki City, Aichi Prefecture, there still exist two traditional brewers of Hatcho Miso; Kakukyu and Maruya, each boasting several hundred years of history and offering visitors a guided tour. Stepping into the storing house of Miso, visitors will encounter rows of huge tubs with round stones stacked high, laid to withstand strong earthquakes. Under those stones weighing a total of three metric tons for each tub, the Hatcho Miso quietly ages. While ordinary white Miso takes usually six months to ferment, Hatcho Miso needs more than two years to mature. This slow aging process gives Hatcho Miso its reddish brown hue and a very distinct flavour, stout and rich with a subtle bitterness and acidity, completely different from white Miso. Since it is so full-bodied, it shines best when it is used to add flavour to an oil based sauce or dairy products.
Another fine example in the region is Heshiko from Fukui Prefecture. Fermented in a bed of rice bran, the salted mackerel develops a deep flavour with intense Umami, brought out with the help of lactobacilli, microbes also found in yogurt. Thinly sliced and lightly grilled, a strip of Heshiko goes well with Japanese Sake, just like the pairing of wine and cheese. For those who wish to learn more about Heshiko and other fermented foods in Fukui Prefecture, the Miketsukuni Wakasa Obama Food Culture Museum, in Obama City (which has no affiliations with the former U.S. President) is a good place to start.