AI Traces How Edo-Period Japanese Jars Evolved Over Centuries
An ordinary storage jar used for water, soy sauce, or even human waste might seem like an unlikely place to look for evidence of a shogunate’s power. A new AI-driven study of Japanese pottery suggests otherwise.
Reading History in an Everyday Jar
Edo-period “Ogame,” or “large jars,” became increasingly standardized over time, developing distinct shapes for everyday and burial use, according to a new archaeological study from the Institute of Science Tokyo. Using AI-assisted techniques and geometric morphometrics, researcher Associate Professor James Frances Loftus analyzed 243 historic vessels to quantitatively track these changes. The findings, published in the journal Open Archaeology on August 19, 2026, provide the first quantitative evidence that major Edo-period historical events shaped not just expensive porcelain production, but ordinary utilitarian ceramics as well.
Measuring Shape Instead of Just Looking at It
Pottery ranks among the most informative archaeological materials, since its shape often reflects both how it was made and used, and the broader historical forces shaping its production. Identifying subtle changes in ceramic form has traditionally relied on visual comparison, which makes it difficult to quantitatively trace how pottery evolved and what those changes reveal about past societies.
Loftus set out to change that by studying how the shapes of Ogame vessels evolved across Japan’s Edo period, spanning 1603 to 1868. The study combined Geometric Morphometrics, a method for quantitatively measuring and analyzing shape, with a Random Forest machine learning model, applying both to the shapes of 243 jars recovered from 11 kiln and mortuary sites across Japan’s Saga and Fukuoka regions. The AI-based approach also let Loftus classify jars that lacked secure dates, addressing a long-standing challenge in historical archaeology.
“Even ordinary household pottery can preserve a surprisingly rich record of technological and social change,” Loftus explained. “By combining GMM with machine learning, this study was able to quantify subtle changes in pottery shape that would have been difficult to recognize consistently through visual observation alone.”
A Jar for Every Purpose
Ogame served as indispensable containers throughout early modern Japan, used for storing water and soy sauce, transporting agricultural fertilizers, collecting human waste, and even serving as burial jars. Supporting both everyday domestic life and funerary ritual, these versatile vessels played a genuinely important role across Edo-period society.
To measure differences in shape, Loftus digitized the outline of each vessel using Elliptical Fourier Analysis, a Geometric Morphometrics technique capable of capturing subtle variations in form. He then trained a Random Forest model to classify undated jars into different chronological stages based on these morphological characteristics.
From Wide Variation to Standardization
The results showed that jars produced during the early 17th century displayed considerable variation in shape, while vessels made during the 18th century became increasingly uniform. That shift toward standardization coincided with major historical developments, including the consolidation of the Tokugawa shogunate, the Qing dynasty’s maritime trade ban, and the expansion of domestic production networks within Japan.
Archaeologists have long argued that these broader historical developments transformed ceramic production in Japan, but that argument had previously focused mainly on expensive, elite porcelain. This study provides the first quantitative evidence demonstrating that the same historical forces were also reflected in the evolving forms of everyday, utilitarian pottery. The shifting patterns suggest that increasing regulation and specialization among ceramic workshops shaped production even as vessels continued to be adapted for specific cultural needs.
Shape Followed Function
Loftus also found that a jar’s shape reflected differences in its intended use. Jars recovered from kiln sites generally had broad shoulders, flared rims, and relatively compact lower bodies, a form well suited for storing and transporting liquids and fertilizers.
Jars excavated from burial sites told a different story. These vessels displayed taller, narrower, and more enclosed structures, indicating they were deliberately designed or selected for funerary purposes rather than simply repurposed from everyday domestic use.
What Ordinary Pottery Reveals That Records Don’t
“This study provides the first quantitative evidence that Edo-period Ogame became increasingly standardized over time while also adapting to different functions in response to broader historical developments,” Loftus said. “Furthermore, it highlights the potential of AI-assisted shape analysis to reveal how subtle changes in pottery morphology reflect wider technological, social, economic, and political change.”
Written historical records tend to focus on political elites and major events, while everyday artifacts like Ogame offer valuable evidence of ordinary people’s lives. By pairing archaeological expertise with AI-assisted analysis, the study shows how material culture can complement the historical record, surfacing social and economic changes that might otherwise remain invisible.
Where This Method Could Go Next
Loftus hopes to eventually combine quantitative shape analysis with other archaeological science techniques, including portable X-ray fluorescence and compositional analysis, to study both Edo-period ceramics and pottery from other regions and time periods. That combination could give archaeologists a more quantitative framework for research worldwide.
Integrating geometric morphometrics with machine learning could ultimately help researchers reconstruct manufacturing systems and study cultural interactions with greater scientific precision, opening new possibilities for understanding past societies through the everyday objects they left behind.
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