During World War I, from 1915 to 1920, about 1000 German soldiers were captured as prisoners of war and taken to an internment camp in Narashino. The Ministry of Agriculture and Commerce took notice of sausage as a highly nutritious food at that time. Karl Jahn and other German prisoners had been sausage makers in Germany. The Japanese bureaucracy made these craftspeople reveal their secret recipe. That’s why Narashino city is called "the birthplace of the traditional process for making sausages."