Kirk here with information about a good quality e-book that has been published about the Aso area.

— start quote — Please have a look! the GIAHS ASO e-book Aso has grown together with its grasslands and is blessed with bountiful farmland, rare plants and animals, and a strong agricultural tradition. These characteristics earned Aso global recognition, culminating in its designation as a World Agricultural Heritage Site in May 2013. With Aso’s designation as a World Agricultural Heritage Site, Kumamoto Prefecture published the GIAHS ASO e-book to explain the unique agricultural traditions of Aso that play a large part in the preservation of the Aso grasslands. GIAHS ASO also contains many great photos of Aso’s breathtaking landscapes. Please have a look! — end quote —

https://furusato.pref.kumamoto.jp/kiji003171/index.html

Personally, I’m not a fan of the e-book format. I’d rather be able to download the whole thing as a pdf. (You can download individual pages of this book but not the whole thing.) Still, it’s nicely done and a good source of information and images, I think.