The JR Sanin Okayama Area Pass provides four consecutive days of unlimited travel on JR train lines in the San’in and Okayama regions. It can be a good pass for exploring the area around Matsue, Iwami Ginzan, Hagi and Tottori, but is even worthwhile for a one-way trip between Okayama and Matsue.
It can be bought on this website, or at major railway stations in the area covered (at a slightly higher cost). Only foreign visitors to Japan (with temporary visitor status) can use the JR Sanin Okayama Area Pass. It cannot be used by residents of Japan.