Kagoshima, Japan (鹿児島) is located in the far south of Japan in Kyushu (九州). It's a beautiful area with a storied agricultural heritage; and it's collectively responsible for around 20% of Japan's Kuroge Washu cattle, the Wagyu breed that produces Japanese A5 Wagyu.
Kagoshima's year-round temperate climate and ecology are well-suited to raising healthy cattle with low stress levels, a necessary component of achieving A5 quality. This region might take the cake for producing happy cows.
And it pays off in taste: Japanese beef connoisseurs consider Kagoshima to produce some of the very best quality A5 Wagyu in the country.
Update: Kagoshima beef took the top prize at "The Wagyu Olympics" (全国和牛能力共進会) this year based on overall contest scores (総合得点による「団体賞」は、鹿児島県が１位). You could say that Kagoshima's A5 Wagyu is the best beef in Japanese beef right now!
Kobe Beef, a brand of luxury beef in Japan, is beef raised in Hyogo prefecture further to the north, and which has earned a rating of A4 or A5 rating from the Kuroge Washu breed of cattle. Kagoshima A5 Wagyu is therefore the same breed of cattle with as good or higher-quality rating, and from an area with ideal conditions for cattle-rasing.
As of 2016, Kobe Beef is rare outside of Japan and was only served in 8 restaurants in total in the United States, fetching prices up to $880/pound (no joke). Kagoshima A5 Wagyu is more limited, and rarer outside of Japan.
Why limit something so good? Well, there's currently a quota on the amount of Japanese Wagyu that can come into the U.S. And don't waste your breath asking Japan's government about exporting DNA or live animals -- there's a total ban on that. Anyway, your time is probably better spent slicing up and savoring the perfectly marbled meat that's been imported for your tasting pleasure. Go to it!