Miso: The Paste That Fed Samurai and Still Starts Breakfast

Open a fridge in Japan and there is a fair chance a tub of miso is sitting in it, somewhere between everyday staple and quiet national treasure. It goes into soup at breakfast, onto grilled aubergine, into marinades and dressings, and it has been doing jobs like these, in one form or another, for well over a thousand years. Few foods get to be both a luxury and a survival ration in the same career. Miso managed it.

First, what it actually is

Miso is a fermented paste made from steamed soybeans mixed with salt and koji. Koji is the helpful mould, Aspergillus oryzae, grown on a base of rice, barley or soybeans, and the base decides the family: rice miso, barley miso or soybean miso. Time does the rest. A short fermentation gives a pale, mild, sometimes sweet paste. A long one gives a dark red paste with a much bigger voice. Colour, in miso, is mostly a record of patience.

That range is why there is no single Japanese miso. Cold regions tended toward salty, long keeping pastes. Warmer regions made barley miso. The soybean only style of the Chukyo region, aged for one to three years, comes out dark and intense. Families once made their own and guarded the flavour of the house. The phrase temae miso, roughly "my own miso", is still Japanese shorthand for blowing your own trumpet.

It arrived as an idea, then Japan made it miso

Fermented soybean pastes came to Japan from the continent in ancient times. Japan's agriculture ministry records one theory that miso itself was introduced from Goguryeo, a Korean kingdom, in 666. Early Japanese documents use words read as misho, close ancestors of the modern word, and for centuries the paste was a precious thing: eaten in small amounts, dabbed onto food rather than cooked with, and valuable enough to feature in the world of courts, temples and high officials rather than ordinary kitchens.

Two things changed that. Soybean harvests grew, and in the medieval period production escaped the temples. Villages and farm households began making their own, and miso started its long slide from luxury to necessity, which is usually where a food becomes interesting.

The mortar moment: soup is born

For most of its early life, miso was grainy and was eaten as it came. The turning point, tradition credits to Zen monks in the Kamakura period, was a tool: the grinding mortar, brought from China. Ground smooth, miso dissolves in hot water. Miso soup, as a thing you drink, dates from that moment.

The samurai adopted it fast. Their plain meal format, ichiju issai, one soup and one dish alongside rice and pickles, put a bowl of miso soup at the centre of the day. It was warm, it was quick, it kept, and it made a simple meal feel complete. By the Muromachi period, commoners were drinking it too, and most of the miso cooking Japan still knows was taking shape in home kitchens.

War food, taken seriously

In the Warring States period, miso became logistics. It travels well, it keeps for months, a small amount flavours a large pot, and it carries real nourishment from the soybeans. Soldiers carried portable forms of it, including miso balls and taro stems simmered in miso that could be cut and dropped into hot water for instant soup on campaign.

The warlords invested accordingly. Takeda Shingen promoted the miso that became Shinshu miso. Date Masamune, founder of Sendai, went furthest of all: after the Sendai miso he took on campaign in Korea reportedly outlasted the miso of other clans, he set up an official miso works, the Goensogura, in his castle town to supply his troops. Sendai miso, a salty red rice miso, later sold in Edo and made the city famous for it. A food good enough to plan a war around tends to survive the peace.

Breakfast, and everything after

By the Edo period, miso shops flourished in the growing cities, regional misos travelled, and miso soup settled into its permanent role: the bowl that starts the Japanese day and accompanies almost any meal built on rice. It remains a living food in the literal sense, and cooks still treat it gently, stirring it in toward the end and keeping it off a hard boil, out of respect for its aroma.

It also never stopped at soup. Miso glazes fish, sweetens dengaku tofu, dresses aubergine, pickles vegetables and, in our century, turns up in ramen bowls, caramel and ice cream wherever a cook wants depth without shouting. The paste that began as a court luxury now flavours both the most traditional breakfast in Japan and the most experimental dessert menu in London. Range like that is earned slowly. In miso's case, at fermentation speed.

Wear the soup

Our Miso Hot Ramen Bowl Hoodie is for anyone who believes a bowl of soup can carry thirteen centuries of history and still be lunch. The warlords planned campaigns around this paste. Planning an outfit around it is considerably easier.