About this site

SUMIMAE is a free map tool for choosing where to live in Tokyo and its commuter belt — for buying a condo or renting. It cross-evaluates open public data (prices, rent, commute time, flood and liquefaction risk, safety, and more) across 48 municipalities on a single map.

SUMIMAE is Japanese: sumu mae. It means what the line says — Before you move.

Two principles run through everything here:

No verdicts. The site does not declare a place “dangerous” or “a good buy”. It shows the data, where it comes from, and how it was processed — the judgment stays yours.
Nothing hidden about sources. Every dataset’s origin, date, and processing method is documented in the “About the data” panel inside the map.

Operator

Site name: SUMIMAE
URL: https://sumimae.com
Operated by: Individually operated
Operator: SUMIMAE site operator
Background: A finance professional fresh out of graduate school. This started as an analysis tool for finding the condo I would buy in my twenties.
Contact: Feedback form ／ ysg.project01@gmail.com

Data and disclaimer

Everything shown on this site is reference information derived from public data — not the published figures of the originating agencies themselves. Market prices and rents are estimates, commute times are door-to-door approximations, and hazard information reflects each agency’s assumptions. We strive for accuracy but do not guarantee it, and we accept no responsibility for decisions or actions based on this site. Always confirm final decisions on-site and against the original sources (official documents, explanations of important matters, and so on).

Credit required by Article 7 of the Real Estate Information Library API terms (MLIT). Only the Japanese wording is authoritative: 「このサービスは、国土交通省の不動産情報ライブラリのAPI機能を使用していますが、提供情報の最新性、正確性、完全性等が保証されたものではありません」 (This service uses the API function of MLIT’s Real Estate Information Library; the timeliness, accuracy, completeness, etc. of the information provided are not guaranteed.)

The full list of sources, dates, and processing methods is in the map’s “About the data” panel.

Advertising policy

This site currently carries no advertising. To fund its operation, it may in the future join affiliate programs (performance-based advertising). If it does, the following rules apply:

Advertising links are labeled as such (e.g. “PR”), in line with Japan’s stealth-marketing regulations.
Data results — prices, scores, rankings, map colors — are computed independently of advertising. Whether an advertiser exists, and who it is, has no effect on what the data shows.
The “no verdicts, sources shown” principles above apply to advertising contexts as well.

Established: August 12, 2026