Oita is a prefecture in Kyushu. It was very hot just like the hell! Summer to the place must be the demons who only torture us.
Joking aside.
To people in Osaka including me, Oita is nothing but one prefecture of Kyushu. But it's said not so to the ones in other prefectures of Kyushu. In Kumamoto next to Oita, they say their parents tell their children not to get married with Oita people. Of course, it depends upon.

A Sight in Beppu-shi, Oita
Oita is surrounded by some high mountains which almost check the advance from other prefectures. Then, people are mostly difficult to get in Oita. That might be a reason why Oita people are so disliked by other prefectures' ones. They must guess that Oita is almost an uninhabited area.
Now, Oita is rich of rivers. They have some first-class rivers like Chikugo River and Oita River, which means there are a lot of underground water. It also means they can easily get good natural water which made them brew miso and soy-sauce a lot there.

Kabosu-sumiso (Fujijin Shoyu) 178 yen (tax in)
Like
Kani-shoyu since 1600 and
Fundokin Shoyu since 1861, you can find several long-established breweries in Usuki, Oita. Their products are marvelously popular among Oita people.
Moreover, kabosu (type of citrus fruit) is one of Oita specialties. At the stores in Oita, lying are soy-sauce with kabosu and the kabosu ponzu vinegar like a product by
Fujiyoshi Shoyu.

Fujiyoshi Shoyu Inc. (Beppu-shi)