Tobishima Island was formed by submarine volcanic activity when the Sea of Japan was expanding. The materials ejected from the submarine volcanoes accumulated on the seafloor and were later uplifted, becoming an island. The Arasaki Coast is made up of a rock called lapilli tuff, which contains pumice and rhyolite fragments from the eruptions.

The area around Arasaki Coast is home to a rare combination of plants—beach plants, rocky coast plants, and grassland plants—including the characteristic Tobishima daylily (Hemerocallis dumortieri var. exaltata) and sukashi-yuri lily (Lilium maculatum). In 1975, it was designated by Sakata City as a natural monument, “Tobishima Arasaki Neck Region Plant Community.” It was also selected in 1996 as one of the 100 Best Coasts of Japan. The sunset seen from here is beautiful.

Every year, environmental conservation activities are carried out in this area, such as island cleanup activities and Tobishima daylily preservation activities.
Two large rocks lie on the abrasion platform near here. Called “jiji-ishi” and “baba-ishi” (“grandpa and grandma rocks”), they are thought to have been carried here by a tsunami.