Why Natto is Associated with Ibaraki Prefecture

In an earlier post I mentioned that I associate natto with Ibaraki Prefecture. But I am not alone. Many people make that association and consider it, especially Mito City, the home of natto, Japan's famous fermented soybean dish. 

This strong association dates back centuries to the Heian period. According to popular legend, the samurai Minamoto no Yoshiie and his troops camped near Mito during a military campaign. Boiled soybeans packed in rice straw for their horses accidentally fermented in the warmth, creating the sticky, pungent food enjoyed today. 

Reportedly, commercial production took off in Mito during the late 19th century, fueled by the arrival of the Joban Railway Line. Merchants sold straw-wrapped natto directly to travelers at Mito Station, turning it into a must-buy regional souvenir that spread its reputation across the country.

Today, Ibaraki remains Japan’s top natto producer, proudly celebrating its culinary heritage with natto-themed mascots, station monuments, and inventive local dishes like natto tonkatsu and even natto ice cream.

Do you eat natto?