A junk is an ancient Chinese sailing ship design that is still in use today. Junks were efficient and sturdy ships that sailed long distances as early as the 2nd century AD, although whether this is indeed a date by which the hull form which we know as the junk’s had found its final form is extremely dubious. Most scholars consider it was the early Song Dynasty (c.10th century CE) before the fully developed hull forms and rigs were in regular use in offshore trade. The fully developed junk design exhibited innovative, though subsequently very little further developed sail plans and hull designs. There is no evidence that these were adopted in Western shipbuilding by direct emulation. In this case, as in so many others, parallel invention, often in response to quite different hydrodynamic, aerodynamic or technical stimuli, is the historically better evidenced explanation.