Saga-kei is one of the three major rivers in Japan, along with Geibake-kei in Iwate Prefecture and Yabake-kei in Oita Prefecture, and is the area around the peninsula jutting out from the southeastern tip of Oku-Matsushima (Miyatojima).
In contrast to the curving landscape of Matsushima Bay, the panorama of rugged rocks is surprising and impressive.