in an uninhabited islet located in the center of à Âfunato Bay, on the Sanriku Coast of Japan. It has been designated a National Place of Scenic Beauty and Natural Monument since 1946.
The islet, which has a land area of , a circumference of 0.9 km and a height of 25 meters, is located within the municipality of à Âfunato, Iwate Prefecture. It is covered in a dense forest of maple and Japanese red pine, such that in autumn the red leaves and red tree trunks give the island the appearance of being made of red coral. It was designated as a national scenic spot for its beautiful scenery.
The island was owned by Shibuya Kasuke, a local businessman who made his fortune importing gunpowder and munitions during the Meiji period. It was donated to à Âfunato village during the Taishà  period for use as a public park. The island suffered from damage caused by tsunami in the 1933 Sanriku earthquake and the 1960 Valdivia earthquake, and in the 2011 Tà Âhoku earthquake and tsunami.