Onychoteuthis borealijaponica, the boreal clubhook squid, is a species of squid in the family Onychoteuthidae. It is the largest member of the genus Onychoteuthis, reaching a mantle length of 30 cm in males and 37 cm in females. Maturity is reached at 250 mm for males, and 300–350 mm in females. There are 24–27 hooks on each club. It is a pelagic species native to the North Pacific, although it migrates into Subantarctic waters during the summer.