This article contains news of a sad incident that occurred in Taragi-machi, near Hitoyoshi:
“In Taragi, Kumamoto Prefecture, two parents jumped into the Kuma river to save their five-year-old daughter who had been playing, but both drowned in the process. A stranger nearby who witnessed the incident jumped in and saved the girl.”
The Kuma River (Kumagawa) has some of Japan’s fastest flowing areas:
“One of the main experience-based tourist attractions in the Hitoyoshi/Kuma district is going down the Kuma River, which is famous as one of the three swiftest rivers in Japan. "
http://www.visitkyushu.org/2013/03/29/kumagawa-river-rafting/