 The Sishuang islands () in Haidao Township, Xiapu County, Ningde, Fujian, China (PRC) are north-northwest of the township.The deepest point in the waters around the Matsu Islands is off the coast of Dongyin.After passing Liang Island (also referred as Wave Islet), ships riding from Nangan encounter stronger waves, which explains why Dongyin was originally called Tungyung (Dongyong).