The structure of the Sea of Japan can be divided into two layers: the surface water layer is about 300 meters deep, and the deep sea layer is below this. Currents in the surface layer move in the counterclockwise direction. One of them is the Tsushima Current, which is a warm current from the Korean Straits to the north-east direction along the shore of the Japanese Archipelago and mainly considered to be the branch of the Kuroshio Current. The other is the Liman Current, which is a cold current from the Strait of Tartary to the south-west direction along the shore of the Eurasian continent.