The study, conducted by Shi Jie Zhu of Yale University’s Department of Anthropology, adopts a methodological framework known as the chaîne opératoire approach to mortuary analysis, adapted from Anke Hein’s 2017 work on prehistoric graves in southwest China. Rather than treating tombs as static containers of wealth, this approach examines burials as the outcome of sequences of social practices, each stage shaped by the decisions of the mourners who performed them. Grave construction, the process of body interment, the selection and arrangement of grave goods, and the spatial location of graves and cemeteries across the landscape are all treated as meaningful actions that can be reconstructed and compared. This stands in deliberate contrast to conventional interpretations that infer social status primarily from the quantity and quality of grave goods, a method that has tended to produce images of rigid, multi-tiered social pyramids in the Liangzhu literature.

The Liangzhu culture, which flourished during the late Neolithic period in the lower Yangtze region, is renowned for its extraordinary jade craftsmanship, its densely clustered settlement landscape, and above all for the massive hydraulic system built on the periphery of the Liangzhu ancient city. Previous research, including a landmark 2018 study in the Proceedings of the National Academy of Sciences, dated this water management enterprise to around 5,100 years ago, making it one of the earliest large-scale hydraulic projects known anywhere in the world. Dams, levees, and canals required the coordination of enormous quantities of labor and materials, raising a question that has long preoccupied archaeologists: what kind of social organization could mobilize, organize, and sustain such collective effort? The new study addresses this question directly by asking whether and how social differentiation within the site complex changed during the periods immediately surrounding the hydraulic construction.

Zhu’s chronological comparison of burial practices yields a striking result. During the Early Liangzhu period, differences among graves and cemeteries existed, but they appear to reflect various forms of group identity, with distinct communities differentiating themselves through particular combinations of grave forms, burial treatments, and object assemblages. The patterns suggest that access to labor and to raw material resources was distributed unevenly across the landscape, but not yet consolidated into a single, tightly ranked hierarchy. Different burying groups, in other words, drew on different pools of resources and followed somewhat different funerary traditions, producing a mosaic of local practices rather than a uniform social order.

That mosaic changed during the early Middle Liangzhu period, the very phase marked by the construction of the large-scale hydraulic system near the site complex. The analysis indicates that several communities and individuals began to attain distinct access to various resources and possibly to social power during this time. In practical terms, this means that certain grave loci show enhanced investment in construction, more elaborate interment procedures, and assemblages that signal privileged relationships with jade, fine ceramics, and other valued materials, while other contemporary loci do not. The timing is significant: the widening of these distinctions coincides with the phase of monumental water management and urban construction that defines Liangzhu’s place among the world’s early civilizations.

The study’s findings point toward a reciprocal relationship between social differentiation and collective enterprise. Rather than a powerful centralized authority simply imposing monumental projects on a subordinate population, the evidence from the burial record suggests that increasing differentiation within the site complex itself contributed to the coordination of labor and resources necessary for large-scale hydraulic and urban construction. Communities and individuals who gained distinctive access to resources may have played crucial roles in organizing work parties, provisioning participants, and legitimizing their positions through the very display of controlled materials in funerary contexts. In this reading, the elaborate graves of the Middle Liangzhu period are not merely reflections of pre-existing rank but active participants in the making of a society capable of remaking its landscape.

Technically, the chaîne opératoire framework allows the researcher to decompose each burial into analytically separable stages. Grave construction can be assessed through pit dimensions, depth, and any architectural elaboration. Body interment processes encompass the treatment of the corpse, including its orientation and positioning. Object assemblages are examined not simply for total value but for the composition of materials, the presence of specific artifact classes such as jades and ceramics, and their placement within the grave. Finally, spatial analysis considers where graves and entire cemeteries sit relative to settlements, waterways, and the Liangzhu city itself. Considering all these dimensions together, across five sites and two chronological phases, produces a dataset rich enough to distinguish community-level traditions from individual expressions of distinction, something that grave-good counts alone cannot achieve.

The approach also challenges a persistent assumption in reconstructions of Liangzhu society, namely that the famous elite cemeteries with their spectacular jade assemblages represent the top of a rigid, vertically ranked hierarchy that characterized the culture from its beginnings. The new analysis indicates that such reconstructions oversimplify a more dynamic process. Social differentiation during the early Middle Liangzhu period was not a single ladder with fixed rungs but a changing configuration of communities and individuals, each negotiating access to different kinds of resources, labor, and possibly ritual authority. Some distinctions were grounded in differential access to raw materials; others expressed group identities that did not map neatly onto a wealth scale. It was only over time, the study suggests, that some of these distinctions hardened into more durable and consequential forms of social power.

The broader significance of the research extends beyond the Liangzhu case. Archaeologists studying the emergence of social complexity worldwide have long debated whether inequality arises primarily through control of prestige goods, through managerial roles in collective projects, or through the gradual accumulation of hereditary advantage. The Liangzhu burial evidence speaks to all three debates at once, because the hydraulic system and the changing funerary record belong to the same historical moment. Here was a society that, within the span of a few generations, transformed both its landscape and its internal social structure, and the graves of its people preserve the traces of that transformation. For the Neolithic world, the Liangzhu site complex now appears not as a culture that simply inherited hierarchy, but as one in which inequality and monumental capability grew together, each feeding the other in a feedback loop that ultimately produced one of East Asia’s earliest urban civilizations.

The study’s datasets, derived from published excavation reports of sites including Fanshan, Yaoshan, Bianjiashan, and others within or near the site complex, are available from the corresponding author on reasonable request, ensuring that the interpretation of these 82 burials can be scrutinized and extended by future researchers. As Liangzhu continues to attract global attention since its inscription on the UNESCO World Heritage List as an archaeological site attesting to early urban civilization in China, research of this kind demonstrates how careful, practice-oriented mortuary analysis can turn even the most familiar burial assemblages into new evidence. The dead of the Liangzhu wetlands, it turns out, still have much to say about how the first cities and their great waterworks came to be.

Subject of Research: Changing social differentiation during the middle Liangzhu period as revealed by burial practices at diverse grave sites near the Liangzhu site complex.

Article Title: Changing social differentiation during the middle Liangzhu period: clues from diverse burial loci

Article References: Zhu, S. J. (2026). Changing social differentiation during the middle Liangzhu period: clues from diverse burial loci. Asian Archaeology. https://doi.org/10.1007/s41826-026-00131-8

Image Credits: AI Generated

DOI: 10.1007/s41826-026-00131-8

Keywords: Liangzhu culture, Late Neolithic, mortuary analysis, social differentiation, burial practices, hydraulic system, jade, social hierarchy, Yangtze delta, chaîne opératoire, ancient China, archaeology

The burial in question belongs to the Qin state, the polity that would eventually unify China in 221 BCE after centuries of warfare during the Warring States era (roughly 475 to 221 BCE). Qin cemeteries from this period have yielded rich evidence of social stratification, ritual practice, and craft production, but intraoral objects remain rare and poorly understood. When excavators encountered the stone within the dental arcade of the buried individual, its position raised an immediate question that could not be answered by visual inspection alone: had the stone been placed deliberately at the time of burial, or had it entered the oral cavity after death through natural processes such as soil intrusion?

Answering that question required what the researchers describe as a differential bioarchaeological assessment, meaning that multiple competing hypotheses were formulated in advance and tested against independent lines of physical evidence. The first hypothesis held that the stone was a deliberate funerary deposit, inserted into the mouth as part of a mortuary ritual. The second proposed accidental incorporation, in which sediment movement or decomposition of soft tissues allowed a stone from the surrounding fill to migrate into the oral space. A third possibility considered was that the object had a physiological origin, for example as a bezoar or concretion formed within the body itself. Each scenario carries distinct implications for taphonomy, for ritual interpretation, and for the study of ancient beliefs about death and the body.

To discriminate among these scenarios, the team combined macroscopic and microscopic examination of the stone with detailed documentation of its position relative to the teeth, mandible, and cervical vertebrae. The stone’s surfaces were inspected for use-wear, modification traces, and adhering materials. Microscopic analysis sought evidence of deliberate shaping, such as grinding facets, polished planes, or flaking scars that would indicate human manufacture rather than natural stream or soil abrasion. The sediment trapped in the surrounding context, including material between the teeth and within the oral cavity, was compared with the grave fill above and around the burial to determine whether the matrix associated with the stone matched the original depositional environment or showed signs of later intrusion.

The materials characterization extended to mineralogical identification, because the type of stone itself is informative. Techniques such as petrographic assessment, scanning electron microscopy with energy-dispersive X-ray spectroscopy, and Raman or similar spectroscopic methods allowed the researchers to determine the rock’s composition and texture. Comparing that signature with known geological sources in the region provided a preliminary indication of whether the stone was locally available or had been transported. Trace residues on the surface, including possible organic films, mineral encrustations, or precipitates consistent with prolonged contact with dental enamel and bone, were mapped and chemically characterized. Such residues are central to the differential assessment, because prolonged intimate contact with oral tissues should leave a distinctive pattern of surface alteration that a stone accidentally swept into a grave void would lack.

The position of the object within the dental arcade proved especially significant. A stone deposited during burial rites would plausibly rest in a stable, constrained position, often wedged between the mandibular or maxillary teeth, with its long axis conforming to the space available. A stone that migrated after burial would more likely rest beneath the collapsed mandible or on the floor of the burial pit in an unconstrained orientation. The excavation documentation, including photographs, three-dimensional recording of the find spot, and stratigraphic drawings, allowed the team to evaluate the object’s orientation and support. Combined with the sediment-matrix comparison and the surface-alteration evidence, the integrated data favored an interpretation of deliberate placement rather than passive intrusion, though the authors are careful to present their conclusions as probabilistic rather than absolute, in keeping with the logic of a differential assessment.

Beyond the mechanics of deposition, the study situates the find within a broader anthropology of mouth deposits. In Chinese funerary tradition, objects placed in the mouth of the dead, sometimes called han in later textual sources, range from jade cicadas in Han dynasty burials to coins, shells, and pearls in other periods and regions. These deposits are commonly interpreted as provisions for the afterlife, symbols of rebirth, or attempts to seal the body against decay and malevolent influence. Jade is the material most often discussed in the textual and archaeological record, which makes a plain stone object from a Qin burial particularly interesting. If the identification of deliberate placement holds, the find suggests that the practice of intraoral deposit was not restricted to elite jade artifacts but extended to humble, locally sourced materials, potentially broadening the social range of the rite.

The bioarchaeological component of the assessment also involved the human remains themselves. The researchers evaluated the dentition for pathology, wear, and post-mortem damage, since the condition of the teeth constrains both the timing of insertion and the physical possibility of placing an object of a given size into the oral cavity. Evidence of periodontal disease, caries, or ante-mortem tooth loss can indicate whether the individual was edentulous at death, which would affect the stability of an inserted object. The age and sex estimation of the individual, together with any observable indicators of health status, provides social context: intraoral deposits may have differed by age, gender, or status within the Qin community, and each well-documented case contributes to building that comparative framework.

Methodologically, the article is a case study in how heritage science can resolve questions that older excavation reports left open. Many intraoral objects discovered in earlier decades were recorded only in photographs or brief notes, and their mode of deposition was asserted rather than demonstrated. The differential approach modeled here, in which hypotheses are specified, tested with independent techniques, and compared for explanatory power, offers a template that can be applied retrospectively to museum specimens and prospectively to future excavations. The authors emphasize that no single technique is decisive: mineralogy, micromorphology, residue chemistry, spatial documentation, and osteology must converge before a deliberate funerary deposit can be argued with confidence.

The find also carries implications for the archaeology of the Qin state specifically. Warring States Qin mortuary practice has often been characterized through large cemeteries, stamped-earth tombs, and later imperial monuments, while small-scale ritual behaviors of ordinary burials are less visible. A carefully analyzed intraoral stone adds texture to this picture, indicating that communities on the Qin periphery participated in symbolic practices concerning the mouth and the passage of the dead, even when exotic materials were unavailable or not socially appropriate. As the dataset of differentially assessed cases grows, it may become possible to trace the geographic spread, chronological development, and eventual textual codification of the mouth-deposit rite, linking the silent stones of excavated graves to the rich corpus of Chinese ritual writing that began to describe such customs in later centuries.

Subject of Research: Bioarchaeological analysis of a stone object deposited inside the mouth of a Warring States-period Qin burial in China

Article Title: Differential bioarchaeological assessment of an intraoral stone object from a Warring States-period Qin burial, China

Article References: Wang, S., Zhang, X., Wang, C., & Zhou, Y. (2026). Differential bioarchaeological assessment of an intraoral stone object from a Warring States-period Qin burial, China. npj Heritage Science. https://doi.org/10.1038/s40494-026-02987-6

Image Credits: AI Generated

DOI: 10.1038/s40494-026-02987-6

Keywords: bioarchaeology, Warring States period, Qin burial, intraoral deposit, funerary ritual, heritage science, taphonomy, ancient China, mortuary practice, dental anthropology, archaeological science, stone artifact