When you go to sushi you expect an offering of miso soup, right? Taken for granted miso was once on par with a gift of silk. Miso was a precious seasoning reserved for royals.
Two schools of thought prevail on the history of Japanese miso. One thought is that a form of miso was used to preserve food as early as the Iron Age. Another touts the idea that miso trailed in on the tails of Buddhism texts from China.