A unique and fascinating sightseeing spot in Kagoshima is the factory shop and storage facility of Sakamoto Kurozu, or as they call it, 'Artisan Amber Rice Vinegar'. A more literal translation is 'black vinegar'. This vinegar is aged under the sun for over a year in huge earthenware jars using traditional techniques dating back over 200 years. Only koji (fermentation starter), steamed rice, and water are used as ingredients, with no additives or coloring. According to a number of research institutions, there are many health benefits to consuming kurozu. For example, it helps combat high blood pressure, aids in digestion by promoting saliva secretion, improves blood sugar control and liver function, etc.
Founded around 1800, Sakamoto Kurozu Inc. is one of Kagoshima's most famous producers of kurozu. In Kirishima City they have a shop, small museum space, and a restaurant overlooking tsubobatake (fields lined with jars full of their product) - with the ocean and beautiful Sakurajima in the background.
Be sure to visit around lunchtime to enjoy dishes made using Sakamoto's delicious vinegar. Lunch sets range from ¥1500 to ¥2000, before tax. I recommend the tokusei (special) set. It contains a pre-meal vinegar drink, tea, a variety of Chinese-style seasonal dishes made with kurozu, pickles, rice, soup, and dessert. The restaurant is open from 10:00 to 17:00, with the last order at 16:00. From 10:00 to 11:00 is 'dessert & drink' time. Special dessert sets are also available from 14:00 to 16:00.
Although there is a small museum, unfortunately, all of the exhibits are in Japanese. There is also a shop selling a variety of products. As for what to buy, consider their regular kurozu that is aged for over a year. Or, try the Kurozu Satsuma which is aged more than two years and has a smoother, milder taste. Kurozu Tenju is their highest quality vinegar and is aged over three years. Another popular product is their Ringo Kurozu, vinegar mixed with apple juice.
For ideas on how to use their vinegar, check out their English website for recipe suggestions - kurozu drinks using honey, apple juice, or milk, and kurozu sauce/dressing.