Valid for 5 (consecutive) days travel on the Japan Rail network in the Seto Inland Sea region, from Kyoto in the east to Fukuoka’s Hakata station in the west, including Matsuyama and Takamatsu on the island of Shikoku. It is also valid on trams in Okayama, on several ferries on the Inland Sea including Hiroshima to Matsuyama, and the short JR ferry journey to Miyajima.
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.