Borneo, also translated as kalimantan island, is the third largest island in the world and a unique island belonging to three countries. These three countries are Indonesia, Malaysia and Brunei. Among them, four provinces in Indonesia account for two-thirds of the total area of the island, which is the largest part, followed by Malaysia (including Sabah and Sarawak), and Brunei only accounts for a small part. The area is 743,330km2. The population is 9.07 million (1980). Borneo Island is located in Southeast Asia. It is located in the center of Southeast Asia. Borneo Island is surrounded by the sea, with a coastline of 1440km. The Sulu Sea is in the northeast, and the Sulawesi Sea (in English) and the Kassia Strait (in English) are in the east. To the south are the Java Sea and Karimata Strait (English: Karimata Strait). To the west and north is the South China Sea. The mountains extend from the inside to the outside, higher in the northeast, with the highest peak in Southeast Asia, Mount Kinabad Lu, at an altitude of 4 102 meters. The terrain is gentle and the rainfall is abundant, and many rivers flow into the sea. The forest coverage rate is 80%. Economic development is limited to the lower reaches of rivers and coastal areas, and most of the main towns are in the estuary. Underground mineral deposits include oil, natural gas, coal, diamonds, copper and gold. Agricultural products include rice, rubber, pepper, sago, coconut and so on. Land transportation is mainly by road. The river is navigable. Oil, copper mining and logging are very important.