The East China Sea (in Chinese Tung hai) is limited to the West by China, to the South. by the island of Formosa, which separates it from the South China Sea, to the East by the Ryū-Kyū Islands, to the North by the coast Japan and Korea. The extended N basin of this sea, beyond the line joining the mouth of the Yang-tze River to the SW end. of Korea, is called the Yellow Sea (Hwang hai), of which the part beyond the Chih-li Strait is an inland sea (in Chinese Pei hai) which forms the two great gulfs of Chih-li and Liao-tung.
The East China Sea is shallow: its depths do not exceed 200 m. if not in the eastern part, where the depth increases more rapidly; to the West of the Ryū-Kyū is the 2000 m isobath. with the maximum depth recorded of 2378 m. Further east, in the Pacific Ocean, there are the deep pits of the Ryū-Kyū and the Philippines.
According to proexchangerates, the climate depends mainly on the thermal conditions of the continent to the West and the Pacific to the East. In the northern part, the temperature drops in the second half of November, so that ice forms at the mouth of the Hwang-ho, which they thicken forming extensive fields in the gulfs of Chih-li and Liaotung; drifting ice can be observed between Che-fu and Ching-wang tao.
The NE monsoon. it settles in October and continues until March, reaching its maximum intensity in the colder months. It is more intense in the northern coasts, which surround China and Korea, less intense in the southern region. In May the summer monsoon begins on the Asian coast, a month later it already occupies the whole area, and then begins to weaken in September; blows from SW. in the southern part, from SE. in the north. Land and sea breezes are sensitive and regular during the summer monsoon, which is therefore less stable than the winter. Violent winds and storms are more frequent in the northern part, particularly in winter. Typhoons originate in the Pacific E or SE. of the Philippines, following trajectories towards W or towards N.-NO., then towards N. and NE., until dissolving in the high latitudes.
The main currents of this sea are the Kuro-shio and the drift currents of the two monsoons. The main branch of Kuro-shio from the N. of the Philippines runs along the coast of Formosa, penetrating the East China Sea; branches penetrate into the Yellow Sea and, through the Strait of Korea, into the Sea of Japan. The average temperature of the waters of this current is about 27 °, ie from 3 ° to 5 ° higher than that of the waters that limit the two sides. Local winds affect Kuro-shio’s directions more than speed. During the NE monsoon. the drift current is directed towards SW. in the western coasts of the East China Sea, it has varying directions in the central region and heads towards S. in the Yellow Sea. When the summer monsoon blows, the sea current is directed towards the NE. along the Chinese coasts; in the eastern part it increases the speed of the Kuro-shio, heading towards the NE. and N. In the western part, the summer currents are irregular, due to the influence of the Yang-tze and the tidal currents, which are intense in the coasts of Korea and in the Chu-san archipelago.
In the East China Sea, the tides behave as in the South. In the syzygies the waters rise about 1 m. in Ta-ku, 2.5 to Che-fu, 3 to 4 in Shanghai and in Kiao-chow Bay, 6 m. in Amoy, of 9.8 in Jinsen (Chemulpo).