The discovery expands the understanding of Neolithic agricultural practices and food regimes in East Asia

A discovery by researchers from the University of Washington at St. Louis and Shandong University – together with an international team of scientists working in China, Japan and South Korea – highlights the historic and domestication of the Adzuki bean through East Asia.

The researchers recovered the leftover of charred Adzuki beans of the Xiaogao site in Shandong, China, dated 9,000 to 8,000 years, at the beginning of the Neolithic age, when humans began to cultivate plants and pets for food. The results – issued in the Proceedings of the National Academy of Sciences September 22 – Push the record for this significant legume of at least 4,000 years in the Yellow River region.

The Adzuki bean (Vigna Angularis) is a basic culture widely cultivated in East Asia which is appreciated both for its nutritional value and its nitrogen fixing properties, which means that it also enriches the soil. It has a cultural meaning and is presented prominently in various kitchens, even today.

According to researchers, the new evidence suggests that Adzuki beans were part of an early neolithic multi-culture system alongside millet, rice and soybeans, in a well-established agricultural tradition in the region of the lower yellow river.

The discovery was part of a broader analysis of the remains of charred Adzuki beans of 41 archaeological sites across East Asia, notably the yellow river, Japan, Korea and the environment of southern China. By combining newly available and previously published data, researchers have also discovered significant regional differences in the size and use of bean, offering a complete overview of the chronology and the evolution of this significant legume.

“Globally, there has been recent importance in the recognition of plant domestication as a prolonged and largely dispersed process – without singular geographic centers,” said Xinyi Liu, professor and associate president of anthropology in Washu Arts and Sciences. “Our results align with this perspective by illustrating parallel developments in the Yellow River, Japan and South Korea during the Neolithic.

“The divergent trajectories of the size of Adzuki beans in the Neolithic yellow river and Japan of the Jomon period are particularly revealing, because they demonstrate that culinary and food practices have played a role in the domestication process as significant as environmental factors.”