Valid for 5 (consecutive) days travel on the Japan Rail network in Okayama, Hiroshima and Yamaguchi Prefectures and the shinkansen (Bullet train) to/from Fukuoka. It can be used on the bullet train service (Sanyo Shinkansen) all the way from Fukuoka’s Hakata station to Okayama. It is also valid on local JR buses around Hiroshima and Yamaguchi.
It can be bought on this website, or at major railway stations in the area covered (at a slightly higher cost). It cannot be used by residents of Japan.