Little soy was eaten in history

Only after WW2 soy became considered a food

This was also the time that soy sauce from Japan began to develop

Only after 1990 soy became popular

 

1917, Japanese companies organized to later become Kikkoman brand soy sauce

1936, USDA developed multiple strains of soybean varieties using hybridizaiton breeding

1941, USDA began farm subsidies and support for soy production

1942, concern about meat shortages and soy protein promoted in America

1957, Kikkoman began exporting to San Francisco

America becomes worlds largest soy producer

Brazil becomes worlds sencond largest soy producer

Europe become world's larges importer of soy