The Japanese big eyed crab, also known as the Japanese big eyed crab in Chinese, is an animal belonging to the sand crab family and the big eyed crab genus. It is distributed in Japan, the west coast of Korea, Singapore, Australia, Taiwan Island, as well as Hainan Island, Fujian, Zhejiang, Shandong, Bohai Bay, Liaodong Bay, Liaodong Peninsula and other places in Chinese Mainland. Japanese big eyed crabs often nest on muddy beaches in the intertidal zone or river mouths near the coast. The width of the head and chest armor of the Japanese big eyed crab is about 1.5 times its length, with surface particles and soft fur, especially dense in males. The stomach area is slightly heart-shaped. The heart and intestinal regions are connected in a "T" shape, and there are two parallel transverse shallow grooves in the gill region. The forehead is very narrow, slightly curved downwards, and there is a longitudinal mark in the middle of the surface.