Tokyo Tackles the Duplicate Image Problem — and Its Approach Diverges From London, Seoul and New York

Tokyo's ward offices and major real-estate portals are sitting on a problem that has quietly grown alongside the city's tourism boom and its overheated housing market: duplicate images — the same photograph uploaded dozens or hundreds of times across government databases, tourism platforms, and rental listing sites — are degrading search results, inflating storage costs, and, in some cases, misleading prospective tenants and visitors.

The issue has sharpened in 2026. The Tokyo Metropolitan Government's digital bureau, based in Shinjuku, has been rolling out a broader data-quality initiative tied to the city's Smart Tokyo 2.0 strategy, which targets improved interoperability across ward-level systems by the end of fiscal year 2026. Duplicate visual assets — everything from redundant street-view thumbnails to recycled Airbnb-style listing photos in Minato and Shibuya wards — have emerged as one of the messier sub-problems inside that larger cleanup effort.

How Tokyo Compares With Seoul and London

Seoul moved earlier. The Seoul Metropolitan Government integrated perceptual-hash filtering — a technique that detects near-identical images even when they've been slightly cropped or recoloured — into its public-facing cultural-heritage portal in 2024, cutting reported duplicate image records by a figure the city government cited publicly at around 40 percent within the first year. The approach was adopted partly because Seoul's tourism authority was hosting tens of thousands of images across multiple legacy systems after the post-pandemic rebound.

London took a different route. Transport for London and the Greater London Authority have leaned on third-party data-governance vendors rather than building in-house tooling, contracting with commercial providers to audit visual assets across the city's tourism and planning portals. The GLA's 2025 digital estate review flagged duplicate media assets as a Tier-2 data-quality risk — significant but not critical — and the remediation timeline stretches into 2027.

New York City's approach has been fragmented. NYC Open Data, the city's public data portal, has no unified image-deduplication policy as of mid-2026; individual agencies manage their own visual content with inconsistent standards. The result is visible to anyone who searches for permit records or parks imagery through the portal: the same photograph of a Midtown building facade can appear under multiple record IDs.

Tokyo sits somewhere between Seoul's proactive integration and London's vendor-reliance model. The city's Bureau of Urban Development has been working with local tech firm teams — several of them clustered in the Shibuya-ku startup corridor near Daikanyama — on perceptual-hashing pilots for the city's property-information systems. Meanwhile, SUUMO, Japan's largest real-estate listing portal operated by Recruit Holdings, began its own internal duplicate-image sweep in late 2025, targeting listings in high-churn rental markets including Shinjuku-ku and Koto-ku, where landlord turnover accelerated as yen weakness pushed up import-linked renovation costs and prompted more frequent re-listing of the same units under cosmetically altered entries.

Why Yen Weakness and Tourism Pressure Compound the Problem

The yen's sustained weakness — which has kept the currency trading at levels that make Tokyo among the most affordable major cities for dollar- and euro-denominated visitors — has driven inbound tourism to record volumes in recent years, generating an enormous flow of user-uploaded imagery into platforms like Google Maps, Jalan, and the Tokyo Convention and Visitors Bureau's own asset library. The bureau, headquartered near Tokyo Station in Chiyoda-ku, acknowledged in its fiscal 2025 annual report that its image library had grown to a scale requiring systematic deduplication protocols, though it did not publish specific figures for the number of duplicate assets identified.

For ordinary renters, the practical consequence is concrete: the same Nakameguro apartment can appear to be three separate listings because a landlord or agent has uploaded identical photos under slightly different addresses or building names, a practice that wastes search time and, in some documented complaints to the National Consumer Affairs Center of Japan, has contributed to confusion during contract negotiations.

The path forward in Tokyo likely means accelerating the integration of hash-based detection tools into ward-level systems before the end of fiscal 2026, rather than waiting for a unified national standard. Renters searching platforms like SUUMO or HOME'S should cross-reference listing photos manually for Nakameguro, Ebisu, and Shimokitazawa — neighbourhoods where re-listing activity is especially high — until those deduplication systems are fully operational.