Iron Encircling Mountains ［鉄囲山・鉄輪囲山］ ( Chakravāda-parvata or Chakravāda;  Tetchi-sen or Tetsurin’i-sen): The mountain range that forms the circular periphery of the world, according to the ancient Indian worldview. It is 312.5 yojanas in height and 3,610,350 yojanas in circumference. Located at the center of the world, Mount Sumeru is surrounded by eight concentric mountain ranges, which are separated by eight concentric seas. The Iron Encircling Mountains are the eighth and outermost of these mountain ranges and are made of iron, while the other seven are made of gold. The sea that lies between this eighth mountain range and the seventh mountain range is salty, while the other seven seas are of fresh water. The distance between the seventh range and the Iron Encircling Mountains, and hence the width of this sea, is 322,000 yojanas. In this outermost sea are four continents: Pūrvavideha, Aparagodānīya, Uttarakuru, and Jambudvīpa, located respectively to the east, west, north, and south of Mount Sumeru.