Octopus sinensis is a marine cephalopod in the family Octopodidae, commonly referred to as the East Asian common octopus. It is native to the western Pacific Ocean, particularly along the coasts of China, Korea, and Japan, inhabiting shallow coastal waters, rocky reefs, and sandy or muddy substrates. The genus name Octopus derives from the Greek oktō meaning “eight” and pous meaning “foot,” referring to its eight arms, while the species epithet sinensis is Latin for “from China,” indicating its geographic association. Long confused taxonomically with Octopus vulgaris, this species has since been recognized as distinct based on morphological and genetic evidence.

Historically and in modern times, Octopus sinensis has been an important seafood species in East Asia, harvested by trap, pot, and small-scale coastal fisheries. Octopus sinensis provides firm, mildly sweet flesh that is consumed in a wide range of preparations. In Japanese cuisine it is used in dishes such as boiled octopus (tako), sashimi, sushi toppings, and vinegared salads; in Korean cuisine it appears as nakji in raw, lightly blanched, or spicy stir-fried preparations; and in Chinese coastal cuisines it is braised, stir-fried, dried, or incorporated into soups. The animal may also be dried whole or in sections for storage and later rehydration. It is strongly associated with Japanese, Korean, and eastern Chinese maritime culinary traditions, particularly in regions bordering the Yellow Sea, East China Sea, and Sea of Japan.

Nutritionally, Octopus sinensis contains several significant nutrients. It is rich in taurine, omega-3 fatty acids including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), vitamin B12 (cobalamin) and selenium. Free amino acids such as glutamic acid, glycine, and alanine contribute to umami and sweetness. Like other cephalopods, it contains small amounts of cholesterol and bioactive peptides that may exhibit antihypertensive activity.