Japanese Hirame and Karei: Flatfish Species and Their Distinctions
Japan — Pacific and Sea of Japan coastal fisheries
Hirame (ヒラメ, bastard halibut, Paralichthys olivaceus) and karei (鰈, Japanese flounder/sole, various Pleuronectidae species) are both flatfish that are frequently confused outside Japan, though Japanese cooks make a precise distinction between them based on eye position: 'Hidari hirame no migi karei' (左平目の右鰈) — hirame's eyes are on the left side of the body when the fish is placed with the dorsal fin upward; karei's eyes are on the right. This simple mnemonic distinguishes the two groups across all species. Hirame is considered more prestigious for sashimi use — the white, firm flesh is among the most delicate in Japanese raw fish culture, with an exceptionally clean, sweet, and mild flavour. The engawa (縁側) — the narrow fin muscle that runs along the edge of the fish body — is particularly valued: the constant movement of the fin develops this muscle into a firmer, richer, more intensely flavoured cut that is priced higher than the main body flesh in sushi bars. Karei (which includes a wide range of flounder species) is generally considered less premium but is excellent simmered (karei no nitsuke — braised flounder in soy and mirin). Both fish are winter-season premium products. The skin of both species is also served: karashime (lightly salted and acid-treated skin) is a delicacy at high-end sashimi restaurants.