Chūgoku region
The San'in subregion is a subregion of Chūgoku region that composes of the prefectures of Shimane, Tottori, and sometimes the northern portion of Yamaguchi Prefecture. The northern portion of Yamaguchi Prefecture composes of Abu, Hagi, and Nagato. The San'yo subregion is a subregion of Chūgoku region and is composed of the prefectures of Hiroshima, Okayama, and Yamaguchi in its entirety.