What this does: type a Japanese address (or paste coordinates) and this page gives you one-click links that open Japan's official hazard map, the Geospatial Information Authority's map, and MLIT's Real Estate Information Library already centered on that spot, with the right hazard layer switched on. Those three government sites are excellent, but their menus and legends are in Japanese. Below the tool you will find an English guide to what each layer means, how to read its colors, and what the Japanese legend labels say.
Independence note: the three map services below are run by the Japanese government — the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) and the Geospatial Information Authority of Japan (GSI). Akiya Check is a separate, private information service and is not affiliated with, endorsed by, or connected to MLIT or GSI. This page only builds links to their public sites; the maps and data belong to them.
Location used:
Run by MLIT and GSI. Each button opens the map at this point with one hazard layer on.
Run by GSI. The base topographic map plus two views of how the land was formed and used.
Run by MLIT. Opens the area-search box with the prefecture and municipality pre-selected when we can detect them; choose the district (地区) and press 地図表示 (show map).
Links open the official sites in a new tab. Their layouts can change without notice; if a link stops landing in the right place, the site itself still works from its home page.
The address lookup uses the address search that GSI built for its own map site. It runs in your browser, and GSI has said that these search functions are intended mainly for its own map and may change or stop without notice. It also only understands Japanese addresses. If you see an error, or the result lands in the wrong town, use coordinates instead — they are exact and work every time:
Coordinates should be latitude first (about 24 to 46 in Japan) and longitude second (about 123 to 154). If you paste them the other way round, the tool swaps them for you.
The Hazard Map Portal Site is run by MLIT's Water and Disaster Management Bureau together with GSI. Its "Kasaneru" (overlay) map gathers hazard data made by national and prefectural agencies into one national map. Two points from its terms of use matter for buyers. First, the portal says its mesh size, drawing method and legends may differ from the hazard maps that the agencies themselves publish, and some places have no data yet. For the latest and most detailed version it points you to the municipality's own hazard map, which you can find through the portal's わがまちハザードマップ (Wagamachi, "my town") link list. Second, it notes that real-estate agents cannot use the overlay map for the legally required pre-contract explanation. So use it to screen, and ask for the municipal map at the important-matters explanation.
Tip: click any point on the map and the portal shows the hazards at that point in a Japanese text pop-up. A browser translator handles those pop-ups well, but check the numbers against the legend below.
The flood button turns on the 洪水浸水想定区域（想定最大規模） layer: the area expected to flood if a river overflows in the largest rainfall the river authority assumes (想定最大規模, "assumed maximum scale"). It is a worst-case planning scenario, not an every-year event. The same button also shows two smaller flood layers where they exist: 内水 (inland flooding, when drains and small channels back up in heavy rain) and ため池 (flooding if an irrigation pond breaks). The depth colors follow the national legend; the plain-English meaning in the third column comes from the portal's own picture key.
| Color | Japanese legend | English |
|---|---|---|
| 0.0〜0.5m 大人の膝までつかる程度 | Up to 0.5 m — roughly knee-deep for an adult | |
| 0.5〜3.0m 1階天井まで浸水する程度 | 0.5–3 m — water can reach the ground-floor ceiling | |
| 3.0〜5.0m 2階部分まで浸水する程度 | 3–5 m — water can reach the second floor | |
| 5.0〜10m 2階の屋根以上が浸水する | 5–10 m — water can rise above a two-storey roof | |
| 10〜20m | 10–20 m | |
| 20m〜 | 20 m or more |
The color swatches on this page are approximations of the portal's colors and are only a reading aid; trust the colors and legend on the official map. What to note: the band at the house itself (not the street), and whether the lot is on the edge of a colored area. Under the portal's "すべての情報から選択" (choose from all information) menu you can also add 浸水継続時間 (how long the water is expected to stay) and 家屋倒壊等氾濫想定区域 (zones next to rivers where the flow or bank erosion could knock houses down) — the second one is a serious flag for a wooden house.
The landslide button turns on the 土砂災害警戒区域等 layers, which prefectures designate under the Act on Sediment Disaster Countermeasures. There are three phenomena, each in its own colors, and two levels:
| Japanese | English | Colors on the map |
|---|---|---|
| 急傾斜地の崩壊 | Steep-slope failure (a slope collapsing onto houses) | 警戒区域 · 特別警戒区域 |
| 土石流 | Debris flow (mud and rock rushing down a stream valley) | 警戒区域 · 特別警戒区域 |
| 地すべり | Landslide (a large block of ground slowly sliding) | 警戒区域 · 特別警戒区域 |
The tsunami button turns on 津波浸水想定, the maximum-scale tsunami inundation that each coastal prefecture sets under the Act on Building Communities Resilient to Tsunamis. The legend uses the same color family as the flood map, but some prefectures add finer bands near the bottom: 〜0.3m (up to 0.3 m), 〜0.5m, 0.5m〜1m, 0.5m〜3m, 3m〜5m, 5m〜10m, 10m〜20m and 20m〜. Even 0.3–1 m of moving tsunami water is dangerous to people on foot, so for a coastal house also check how far it is to higher ground — the evacuation-site symbols (指定緊急避難場所) can be added from the portal's menu.
The liquefaction button shows 地形区分に基づく液状化の発生傾向図, a national map that ranks each roughly 250 m mesh by how easily its type of ground has liquefied in past earthquakes. It is a screening map, not a prediction for one lot. The legend runs from 強 (strong tendency) at the top to 弱 (weak) at the bottom:
| Color | Japanese legend | English |
|---|---|---|
| 埋立地や旧河道など | Strongest: reclaimed land, former river channels, etc. | |
| 干拓地や自然堤防など | Drained lakebed/sea land (polders), natural levees, etc. | |
| 緩勾配の谷底低地、緩勾配の扇状地など | Gently sloping valley floors and alluvial fans | |
| 急勾配の谷底低地、急勾配の扇状地など | Steeper valley floors and alluvial fans | |
| 山地や丘陵など | Weakest: mountains and hills |
Liquefaction is not part of the flood-map explanation an agent must give before a contract, so this layer is one you have to check yourself. Our longer guide explains what to do with the result: how to check liquefaction risk for a Japanese house.
GSI Maps is the national topographic map. It does not draw hazard zones, but it shows the shape and history of the land, which explains why a lot is on the hazard map.
The Real Estate Information Library is MLIT's property-information site. Its map combines prices, hazards, zoning and population on one screen. The tool above opens its area-search box with your prefecture and municipality pre-filled when the coordinates can be matched to a municipality code; choose the 地区 (district) and press 地図表示 (show map). The top menu translates as follows:
| Menu | Useful items inside |
|---|---|
| 価格情報 — Prices | 不動産取引価格情報 (transaction prices reported by buyers) · 成約価格情報 (closed-deal prices from the agents' network) · 国土交通省地価公示 / 都道府県地価調査 (official land price benchmarks) |
| 地形情報 — Terrain | 陰影起伏図 (shaded relief) · 土地条件図 (land condition map) · 大規模盛土造成地マップ (large fill-land developments) |
| 防災情報 — Disaster prevention | 洪水浸水想定区域 (flood) · 土砂災害警戒区域 (landslide zones) · 津波浸水想定 (tsunami) · 高潮浸水想定区域 (storm surge) · 災害危険区域 (disaster hazard districts with building limits) · 急傾斜地崩壊危険区域 · 地すべり防止地区 · 液状化の発生傾向図 (liquefaction) · 災害履歴 (past disasters) · 指定緊急避難場所 (evacuation sites) |
| 周辺施設情報 — Nearby facilities | Nurseries, school districts (小学校区 / 中学校区), medical and welfare facilities, libraries, town offices |
| 都市計画情報 — City planning | 区域区分 (urbanization area vs. control area) · 用途地域 (land-use zone) · 防火・準防火地域 (fire-prevention districts) · 都市計画道路 (planned roads) · 地区計画 · 立地適正化計画 |
| 人口情報等 — Population | Census population in a 250 m mesh · 将来推計人口 (projected future population) · station passenger numbers · densely inhabited districts |
Two layers here are not on the hazard portal and matter a lot for cheap rural houses: 災害危険区域 (a disaster hazard district where a municipality can restrict building homes) and 区域区分, which tells you whether the lot is in an urbanization control area (市街化調整区域) where rebuilding can be restricted. For prices, see our guide to checking sold prices on Reinfolib.
Hazard maps answer one question — what nature might do to this spot. They say nothing about whether you are allowed to rebuild the house if it burns down (再建築不可), whether the lot touches a legal road, whether there is a septic tank, a leasehold or a disclosure matter in the listing, or whether the asking price is in line with recent sales nearby. Those facts sit in the listing text, the zoning layers and the transaction records, and you have to cross-check them one by one. Our hazard map guide for akiya buyers walks through the flood, landslide and tsunami checks in more depth, including what the agent must disclose.
The map shows part of the picture. The report puts it all on one page. An Akiya Check report reads the listing you are looking at and combines the hazard layers above with rebuild restrictions, land-use zoning, utilities, transaction prices and population trend for that exact lot — in English, with the questions to send the agent in Japanese. Unknowns are marked unknown, never guessed.
Single report $49 · Compare 3 for $99 Free 12-point checklistThe Kasaneru Hazard Map and its legends are in Japanese, and the municipal hazard maps are usually Japanese PDFs. Some cities publish English or multilingual hazard maps, so search the municipality's website as well. This page gives you English explanations of the national map layers and links straight to the right spot, but the maps themselves stay in Japanese.
The address search this tool uses is GSI's Japanese address search, and in our tests it returned no results for romanized addresses. Copy the Japanese address from the listing (the 所在地 line), or paste latitude and longitude from Google Maps. Coordinates are also more precise than a partial address, which may only match the town centre.
No. A blank area can mean the modeled risk is low, or that no data has been prepared for that hazard there yet; the portal itself says some places are not yet mapped. Hazard maps are also based on assumed scenarios, and real events can exceed them. Check each layer separately and confirm with the municipality's own hazard map.
The tool is free and runs in your browser. The address you type is sent directly from your browser to GSI's address search and reverse-geocoding services to find the coordinates and municipality, and the map links open the government sites in a new tab. This page does not save the address. Our analytics record page visits and button clicks, not the address text.
No. Since 28 August 2020 the agent must show you the property's location on the municipal flood hazard maps during the important-matters explanation (重要事項説明), and the portal's terms say its overlay map cannot be used for that explanation. Use these maps to screen properties early, then compare with what the agent shows you and ask about any difference.
This page is general information. Map layers, legends and site layouts belong to the Japanese government services named above and may change; always read the current legend on the official map. Akiya Check is not affiliated with MLIT or GSI. Nothing here is legal, tax, or real-estate brokerage advice — confirm every point for a specific property with the agent, the municipality, and licensed professionals.