Tokyo Public Archives Lose Millions to Duplicate Digital Images

Tokyo's major public digital archives collectively hold tens of millions of image files, and a growing share of those files are exact or near-exact duplicates. That is the finding driving a quiet but accelerating conversation inside the Metropolitan Government's Digital Services Bureau, which oversees the city's data infrastructure across all 23 special wards. The scale of the redundancy problem is larger than most administrators had anticipated when Tokyo began its serious push toward paperless operations after 2020.

The timing matters because the city is mid-stream in a digitalisation programme that intersects with two expensive priorities: servicing a record inbound tourism surge — visitor numbers to the Tokyo metropolitan area are tracking well above pre-pandemic levels — and building out data systems for an aging society that increasingly relies on digitised care records and telemedicine image files. Duplicated assets inflate cloud storage costs, slow retrieval systems used by frontline care workers and gum up the visual search tools that the Tokyo Metropolitan Tourism Council relies on to supply licensed imagery to travel platforms worldwide.

Where the Redundancy Is Concentrated

The problem clusters in a handful of institutional contexts. The Tokyo Metropolitan Library system, headquartered in Minami-Azabu, Minato Ward, has been digitising its photographic collection since at least 2018. Archivists working on that project have identified categories of routine municipal photographs — infrastructure inspections, ward office events, school ceremonies — where the same image was ingested under different filenames by different departments. In some document batches, duplication rates reportedly exceed 30 percent of total file count, according to internal reviews that have been described in general terms at open Digital Services Bureau briefings.

The Bureau of Urban Development, which maintains tens of thousands of planning and survey photographs tied to redevelopment projects in areas like Toranomon and the ongoing Shibuya Station district renovation, faces its own version of the problem. Contractors submit progress photographs at multiple project stages, and without a centralised deduplication checkpoint, the same site images routinely appear under multiple project identifiers. Storage costs for the bureau's image holdings have risen sharply as cloud pricing in Japan has climbed alongside yen weakness, which pushes up the yen cost of services priced in US dollars.

The Numbers Behind the Waste

Cloud object storage pricing on the major platforms used by Japanese public bodies now typically runs between ¥2.5 and ¥4.5 per gigabyte per month for standard access tiers, with retrieval costs layered on top. A single uncompressed municipal survey photograph can run to 20 megabytes or more. Multiply a 30 percent duplication rate across an archive of even one million files and the redundant storage burden runs into hundreds of terabytes. At mid-range pricing, that represents an annual waste potentially exceeding ¥10 million for a single large bureau — before retrieval and bandwidth costs are counted.

The issue has also surfaced inside Tokyo's disaster preparedness infrastructure. The Tokyo Fire Department, which stores damage assessment photographs from incidents across the city's 18 fire districts, began a systematic deduplication audit in early 2025 after finding that a single February 2024 fire in Adachi Ward had generated more than 1,400 image files, of which preliminary review suggested roughly 400 were functional duplicates created by multiple responding units uploading the same frames independently.

Deduplication software — tools that use perceptual hashing to identify visually identical or near-identical images — has been widely available for years. The gap in Tokyo, as in many large bureaucratic organisations, is not the technology but the governance: no single policy mandates a deduplication checkpoint at the point of ingestion across all metropolitan departments. The Digital Services Bureau published draft data management guidelines in March 2026, with a public comment period that closed in May, that would for the first time require all new archival uploads above a threshold file size to pass through a hash-check filter before being written to permanent storage.

If those guidelines are adopted as formal policy — a decision expected before the end of the current fiscal year in March 2027 — every metropolitan department from the Bureau of Waterworks in Bunkyo Ward to the Board of Education would be bound by the same ingestion standard. The practical payoff, administrators argue, goes beyond storage savings: faster image retrieval for care facilities in Setagaya and Nerima wards, cleaner data sets for the tourism promotion tools and less bureaucratic friction when different departments need to share visual records for joint planning. The draft guidelines are available on the metropolitan government's open-data portal for any organisation that wants to model its own approach before the formal deadline arrives.