Tohoku, which makes up the entire northeast of Honshu, Japan’s main island, is essentially the country’s New England, with colorful foliage in the fall and extremely snowy winters. It’s also where samurai cuisine rose to prominence in the 1600s, during the important Edo period. Back then, Japan’s prized athletes typically ate a simple diet of miso soup and brown rice to carbo-load for battle. Adding textural variety and strong flavors helped encourage them to consume more grain, so kitchens of the era experimented with adding distinctive, salty side dishes: pickled vegetables and plums, seaweed, and natto, a fermented soybean paste.