Every so often, a discovery reshapes the way we think about the beginnings of human civilization. Such is the case with a groundbreaking study led by researchers from Washington University in St. Louis and Shandong University, in collaboration with scientists across China, Japan, and South Korea. Their work, recently published in the Proceedings of the National Academy of Sciences, pushes back the known history of the adzuki bean by thousands of years, revealing its role in the earliest chapters of East Asian agriculture.
At the Xiaogao site in Shandong, China, archaeologists unearthed charred remains of adzuki beans dated to between 9,000 and 8,000 years ago. This was a time when humanity stood on the threshold of profound transformation: the Neolithic age, when people began to shift from foraging to farming, from nomadic lives to settled communities. In those small, charred fragments of bean, we glimpse not only the diet of early farmers but also the complex process by which plants became woven into human society.
The Bean That Fed Civilizations
The adzuki bean (Vigna angularis) may not carry the global fame of rice or wheat, yet in East Asia it has been a cornerstone of both sustenance and culture for millennia. Today, adzuki beans remain beloved across the region: in Japan, they are sweetened into red bean paste that fills confections; in Korea, they enrich rice cakes and porridges; in China, they appear in both savory stews and celebratory desserts.
But adzuki beans are more than a cultural delicacy. Nutritionally rich and packed with protein, they also play an invisible role in farming: as legumes, they fix nitrogen in the soil, naturally fertilizing fields and ensuring the health of future crops. This dual benefit—food for people and nourishment for the land—made adzuki beans invaluable to early farmers building sustainable systems of agriculture.
A Complex Picture of Domestication
The new study does more than mark an earlier date for adzuki bean cultivation. It sheds light on how domestication unfolded as a diverse, regionally varied process rather than a single, linear story. By examining charred remains from 41 archaeological sites across East Asia—including regions of the Yellow River basin, Japan, Korea, and southern China—researchers pieced together a broader narrative of how humans interacted with this legume.
The evidence points to an early multi-cropping system in the Lower Yellow River region, where adzuki beans grew alongside millet, rice, and soybeans. This diversity was not accidental. Early farmers deliberately cultivated a range of crops, balancing nutrition, resilience, and soil health. In doing so, they laid the foundation for agricultural traditions that still shape East Asian diets today.
Yet the story is not one of uniform development. Differences in the size and usage of adzuki beans across regions highlight the ways culture and cuisine influenced domestication. In the Yellow River valley, beans followed one evolutionary path, while in Jomon-period Japan they followed another. The divergence reflects not only environmental pressures but also human choices—what people preferred to eat, how they prepared food, and what qualities they valued in their crops.
Parallel Paths of Innovation
One of the most striking insights from the research is that adzuki bean domestication occurred through parallel developments in multiple places. For decades, scholars often framed plant domestication as originating in singular “cradles of agriculture,” such as the Fertile Crescent for wheat or Mesoamerica for maize. But the adzuki bean’s story suggests a more nuanced reality: domestication was not a single origin event but a web of overlapping efforts across different communities.
As Xinyi Liu, professor of anthropology at Washington University, explains, “Our results align with the perspective that domestication was a protracted and widely dispersed process—one without singular geographical centers.” In other words, the adzuki bean is not the product of one people or one region but of many human groups experimenting, adapting, and innovating over thousands of years.
Food, Culture, and the Human Hand
What makes this discovery especially powerful is the recognition that domestication is not simply an environmental process but a cultural one. The divergent trajectories of adzuki bean size in the Neolithic Yellow River and Jomon-period Japan show how human taste, culinary techniques, and dietary needs shaped the path of this crop as much as climate or soil did.
Domestication, then, is not only about taming nature—it is about the intimate dialogue between humans and plants. Early farmers did not just select for larger beans or higher yields; they cultivated crops that fit into their food traditions, rituals, and daily lives. In doing so, they crafted agricultural systems that sustained both body and culture.
Why This Discovery Matters Today
At first glance, the dating of charred beans may seem like a niche detail of archaeology. But in reality, it speaks directly to some of the biggest questions we face today. How did humans first learn to sustain themselves with agriculture? What can the deep history of crops teach us about resilience and sustainability in modern farming?
The adzuki bean’s story reminds us that agriculture was never static. It was an evolving, regionally diverse practice shaped by human creativity, experimentation, and cultural preference. In our current age of climate uncertainty, this lesson is particularly relevant: diversity—in crops, farming practices, and cultural approaches—has always been a source of strength.
Moreover, the research highlights the shared heritage of East Asia. Long before national borders, people across the Yellow River basin, the Japanese archipelago, and the Korean peninsula were connected through parallel innovations in agriculture. The adzuki bean stands as a humble yet powerful symbol of this intertwined history.
Seeds of Memory, Seeds of Future
The charred beans recovered from Xiaogao are not just archaeological specimens; they are seeds of memory, carrying within them the story of how humans and plants grew together in mutual dependence. They connect us to farmers who lived 9,000 years ago, people who experimented, tasted, planted, and harvested, setting in motion traditions that continue in every bowl of adzuki bean porridge or red bean pastry enjoyed today.
In a sense, the discovery is not only about the past but also about the future. As we strive to create more sustainable food systems, the lessons from early agriculture—multi-cropping, soil enrichment, regional diversity—offer timeless wisdom. The adzuki bean, small yet mighty, shows us that innovation often begins not with grand designs but with humble seeds nurtured by human hands.
Conclusion: A Bean That Changed the World
The rediscovery of the adzuki bean’s ancient origins is more than an archaeological milestone. It is a reminder that the roots of our food run deep, entangled with human culture, environment, and imagination. By tracing the charred remains of beans across East Asia, researchers have illuminated not just a crop but an entire way of life—one built on resilience, diversity, and the enduring partnership between people and plants.
Nine thousand years ago, farmers in the Lower Yellow River valley planted beans that would outlast their lifetimes. Today, their legacy lives on in the fields, kitchens, and cultural traditions of East Asia, and in the scientific stories that continue to unfold. The adzuki bean, once charred and buried, now returns to light—reminding us that even the smallest seed can hold the weight of history.
More information: Xuexiang Chen et al, The discovery of adzuki bean (Vigna angularis) in eastern China during the 9th millennium BP and its domestication in East Asia, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2510835122
