Like Miyazaki beef, Miyazaki is considered to have been a place of animal husbandry, isn't it? At the end of 2016, they reported that they found some chickens got bird flu within a poultry farm in Miyazaki.
There're many areas whose soil consists of volcanic ash property in Miyazaki, saying like a geologist, therefore it's difficult to say those districts suit rice farming well. So I can suppose they had to take animal husbandry in primary industry there. Moreover, the prefecture is almost in a temperate climate, which fortunately suits animal husbandry.
Aoshima, Miyazaki-shi
It means that Miyazaki seasonings have mostly developed for meat dishes. In the Takachiho are, for example, roast chickens are very popular.
For seasoning meat dishes, they need soy-sauce and mirin. I guess there're more of sweeter soy-sauce at stores in Miyazaki. Like
Kanena in Aoshima and
Hayakawa in Miyakonojo, there're many soy-sauce breweries in Miyazaki.
"Amai-jan" Sweeter Soy-sauce by Kanena
It's supposed that they hardly use salt, on the other hand, according to the 2016 report by Statistic Bureau, Ministry of Internal Affairs & Communications.
Miyazaki beef is not as famous as Omi beef and Matsuzaka beef in Japan, because some of Miyazaki cows are sold whole sale for other areas like Matsuzaka and Omi. Namely, a part of Omi beef and Matsuzaka beef were originally born in Miyazaki. Well, it's a kind of usual OEM like Emporio Armani watches are manufactured by Citizen.