China Sea (Chinese, Nan-hai, Southern sea), that portion of the Pacific cut off from the main ocean by a chain of islands, of which Borneo, the Philippines, and Formosa are the principal. It is bounded E. by this chain of islands, and W. by China, Anam, and the Malay peninsula. On the N. it opens into the Tang-hai, or Eastern sea, through the Formosa channel; on the E. into the Pacific through the Balintang channel, between the islands of Formosa and Luzon; on the S. into the Indian ocean through the sea and strait of Sunda; on the S. W. into the sea of Bengal through the strait of Malacca. Its extreme length, S. W. to N. E., from the extremity of the Malay peninsula to Formosa, is about 2,000 m.; average breadth, W. to E., from the continent of Asia to the chain of islands, about 750 m. It has two deep indentations: the gulf of Tonquin, between China and Anam; and the gulf of Siam, between Siam and the Malay peninsula. The islands are few, Hainan being the only one of considerable size.