A remarkably intact pottery vessel dating back more than 10,000 years has been recovered from the depths of Lake Biwa, Japan, marking one of the oldest and most significant ceramic discoveries in underwater archaeology. The ancient artifact, retrieved from 64 meters beneath the surface at the Tsuzuraozaki underwater ruins, has stunned researchers with its near-perfect preservation, offering unprecedented insights into Japan's prehistoric Jomon period. The discovery was made possible through cutting-edge autonomous underwater vehicle technology originally developed for deep-sea exploration, demonstrating how modern innovation can illuminate humanity's distant past, reports Arkeonews.
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The vessel, measuring approximately 25 centimeters tall with a distinctive pointed base and engraved patterns, has been identified as either Jinguji-style or Konami Upper-layer pottery, placing its creation between 11,000 and 10,500 years ago. This makes it the oldest artifact ever found at the Tsuzuraozaki site, a mysterious underwater location first identified in 1924 when local fishermen accidentally netted ancient pottery fragments in their catch. The discovery adds to the approximately 200 pottery pieces recovered from the site over the past century, spanning periods from the Jomon through to the Heian era.
An almost intact pottery piece found 64 meters deep in Lake Biwa in Shiga Prefecture in October. (Nagahama City Government and the Shiga Prefectural Government)
Advanced Technology Reveals Ancient Secrets
The October survey that uncovered this treasure employed a sophisticated 3-D underwater scanning system equipped with four synchronized cameras, originally engineered for submarine cable inspection. According to Yoshifumi Ikeda, professor of underwater archaeology at Kokugakuin University, the technology produced data quality "comparable to what could be gathered by divers, even at depths exceeding 30 meters." This breakthrough represents a marriage between modern robotics and ancient history, allowing researchers to explore depths that would be dangerous or impossible for human divers to safely navigate.
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The survey was commissioned by the Nara National Research Institute for Cultural Properties in partnership with the Shiga prefectural government. The underwater scanners mapped a 200-by-40-meter section of the lakebed with remarkable clarity, documenting not only the ancient vessel but also six Haji pottery jars dating to approximately 1,500 years ago during the middle Kofun period. The scanning system builds upon years of progress in underwater robotics by Japan's National Maritime Research Institute, whose autonomous underwater vehicles have previously proven their worth in deep-water mapping campaigns and archaeological searches across Lake Biwa's mysterious depths.
Example of Late Jomon period pottery with characteristic cord-marked decoration. (Public Domain)
A Window Into Japan's Prehistoric Culture
The newly discovered vessel belongs to the Jomon period (14,500 BC to 1,000 BC), one of the world's most remarkable prehistoric cultures. The Jomon people were primarily hunter-gatherers who developed sophisticated ceramic technology, creating some of humanity's earliest pottery. The name "Jomon" itself means "cord-marked," referring to the twisted rope impressions that decorated their distinctive vessels. Archaeologists note that Jinguji-style pottery, like the Lake Biwa discovery, is characterized by pointed bases, soft contours, and subtle engraved patterns reflecting some of the earliest experiments in fired clay technology in prehistoric Japan.
The vessel's remarkable condition continues to baffle experts. While artifacts found on land typically suffer from fragmentation and erosion, underwater discoveries often remain protected for millennia. Lake Biwa's unique geological structure plays a crucial role in this preservation. The Tsuzuraozaki site lies within a valley-like depression where depths sometimes exceed 80 meters, with minimal sediment accumulation. Continuous tectonic movements keep the lakebed exposed, preserving ancient artifacts in situ for thousands of years, creating what researchers describe as an underwater time capsule.
Mysteries of the Underwater Site
Despite nearly a century of sporadic discoveries, the full scope of the Tsuzuraozaki ruins remains enigmatic. Scholars continue to debate how these ancient vessels ended up on the lakebed. Possible explanations include ritual deposits offered to water deities, lakeside settlements lost to geological subsidence, earthquake-related land shifts, or fishing communities gradually overtaken by rising water levels during the transition from the last Ice Age. The newly discovered vessel, found upright and intact, may finally provide the contextual clues needed to solve these archaeological puzzles.
Professor Kenichi Yano of Ritsumeikan University emphasized the discovery's unique significance:
"This is a discovery that could only occur underwater. The preservation, location, and context offer insight impossible to obtain from land ruins."
A New Era for Underwater Archaeology
The 10,000-year-old pottery vessel from Lake Biwa not only sheds light on chapters of Japan's ancient history but also marks a pivotal moment where cutting-edge technology converges with traditional archaeology. As autonomous vehicles continue to map previously unreachable underwater sites, archaeologists anticipate a wave of discoveries that will shed new light on how ancient peoples lived, died, and created beauty in an age long before written records.
Top image: An almost intact pottery piece found 64 meters deep in Lake Biwa in Shiga Prefecture in October. Source: Nagahama City Government and the Shiga Prefectural Government
By Gary Manners
References
Arkeonews. 2025. Unbroken After 10,000 Years: Lake Biwa in Japan Unveils One of the World's Oldest Pottery Artifacts. Available at: https://arkeonews.net/unbroken-after-10000-years-lake-biwa-in-japan-unveils-one-of-the-worlds-oldest-pottery-artifacts/
Greek Reporter. 2025. Pottery Vessel Found in Lake Japan. Available at: https://greekreporter.com/2025/11/25/pottery-vessel-lake-japan/
The Asahi Shimbun. 2025. Nearly Intact 10,000-year-old Pottery Found in Lake Biwako. Available at: https://www.asahi.com/ajw/articles/16020388
