Sebastolobus macrochir is a deep-water marine fish species in the family Scorpaenidae, commonly referred to as the broadbanded thornyhead, and known in Japan as kinki, kichiji, or menme. It inhabits the North Pacific Ocean, particularly along the continental slopes off Japan, the Kuril Islands, the Russian Far East, and parts of the northeastern Pacific. The genus name Sebastolobus derives from Greek sebastos, meaning “venerable” (a root also used in naming rockfishes of the genus Sebastes), and lobos, meaning “lobe,” referring to morphological features of the head and fins, while the species epithet macrochir comes from Greek makros meaning “large” and cheir meaning “hand,” likely referencing its relatively large pectoral fins. This species inhabits cold, deep benthic environments and is adapted to high-pressure, low-light ecosystems, where it feeds on crustaceans and small fishes.

Sebastolobus macrochir is highly valued in northern Japanese cuisine, especially in Hokkaidō and the Tōhoku region. It is prized for its rich, fatty flesh despite being a deep-sea species, and is commonly prepared simmered (nitsuke), grilled, or used in soups. Its high lipid content makes it particularly suitable for slow braising in soy-based broths, where the collagen and fats produce a gelatinous, flavorful texture. It is regarded as a premium winter fish in regional markets. It is strongly associated with northern Japanese culinary traditions and cold-water Pacific fisheries.

The species contains eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), taurine, collagen peptides derived from connective tissues and vitamin D. Like other long-lived deepwater rockfish, it may accumulate trace heavy metals depending on habitat, though levels vary by region and management practices. Its nutritional profile reflects its adaptation to cold, deep marine environments, contributing to its culinary richness and dietary value.