Before You Buy or Develop Land, Check for 'Watch Areas' and 'Special Watch Areas' — Now on the Map

Hello from the MAPRISE team. This time we're introducing something we think real-estate professionals and developers in particular should know about: a layer for zones designated under Japan's "Important Land Survey Act."

What the Important Land Survey Act is

The formal name is the "Act on the Investigation and Regulation of the Use of Land in the Surrounding Areas of Important Facilities and on Remote Border Islands, etc." It was enacted in June 2021 and came into full effect on September 20, 2022, as a national-security-oriented land-use regulation.

Its purpose is to prevent land near important facilities — Self-Defense Force bases, Japan Coast Guard facilities, nuclear-related facilities — and land on Japan's remote border islands from being used for activities that would "impede the function" of those facilities, such as radio jamming or cutting off lifelines. The government can investigate how land and buildings in these zones are being used (owner and user names, actual usage), and where an impeding activity is confirmed, it can recommend or order that it stop.

What's the difference between a "Watch Area" and a "Special Watch Area"?

There are two tiers of zone designation.

• Watch Area: designated for roughly a 1,000-meter radius around an important facility's site, or for a border island. Land and buildings within this zone are subject to a usage investigation.
• Special Watch Area: designated within Watch Areas for facilities of particularly high importance (such as Self-Defense Force command headquarters) or particularly significant islands. In addition to being subject to the same usage investigation, selling or transferring land or buildings above a certain size within a Special Watch Area requires advance notification to the Prime Minister (in practice, the Cabinet Office is the actual contact point).

In Special Watch Areas, notification is required before you buy land or build

This is the single most important point in this post. For land or buildings of 200 square meters or more within a Special Watch Area (for buildings, the combined floor area across all stories), if you intend to enter into a sale, exchange, or similar contract, you must notify the government — name, address, purpose of use, and so on — before the contract is signed.

Finding out a site is inside a Special Watch Area only after you've already acquired it can throw off your whole schedule. The flip side is also true: if you know whether a candidate site falls into this category at the screening stage, you can build the notification requirement into your plan from the start.

What real-estate agents should check: the disclosure-statement connection

Whether advance notification is required under the Important Land Survey Act has been added to the list of matters that must be explained in a disclosure statement, under Article 3, Paragraph 1, Item 63 of the enforcement order of Japan's Building Lots and Buildings Transaction Business Act.

One practical detail worth knowing: this item applies only to disclosure statements for sales and exchanges — it does not apply to leases. If you're handling a property within one of these zones as a rental, this item doesn't apply. But if you're handling a sale or exchange, you do need to check whether the property falls within a Watch Area or Special Watch Area.

What developers should check: screening before land acquisition

From a developer's standpoint, we'd recommend checking these zones at the initial site-screening stage. Acquiring or developing land within a Special Watch Area isn't prohibited outright, but the advance-notification procedure means you'll need more schedule buffer than you would for an ordinary transaction. Sorting candidate sites by whether they fall inside one of these zones early on — while you're still comparing multiple options — can save you rework further down the line.

Try it: around Fukuoka City

Here's what it looks like when you turn this on in MAPRISE around Fukuoka City.

Several Watch Areas (purple) are set around Self-Defense Force facilities near Hakata Ward and Kasuga City. At the bottom of the screen, a popup for the Sefuriyama Sub-Base Special Watch Area (red) is also shown.

Try it: Ogori City

Depending on the facility, a Watch Area can cover a surprisingly wide area. Let's look at the area around the Japan Ground Self-Defense Force's Ogori Garrison.

Not just the garrison itself — the surrounding residential neighborhoods are swept into the Watch Area as one connected zone. That scale is hard to appreciate until you actually see it on a map.

Zooming out across Kyushu

Looking at all of Kyushu, Watch Areas and Special Watch Areas are scattered mainly along the coast and near border islands.

You can see zones designated around areas that qualify as remote border islands, such as Iki, Tsushima, and the Goto Islands.

How to read the legend

The legend is simple — two categories: Watch Area (purple) and Special Watch Area (red).

• Watch Area: subject to a usage investigation. No notification obligation.
• Special Watch Area: subject to the same investigation, plus a requirement to notify the Cabinet Office before entering into a sale (or similar) contract for land or buildings of 200 square meters or more.

Being upfront about coverage

This layer currently covers the Kyushu 7 prefectures only. The source is the Cabinet Office's "Important Land Web Map" (as of March 2026, Public Data Usage Agreement Version 1.0). Zone designation itself happens nationwide, but we've started bringing this into MAPRISE with Kyushu first. Nationwide coverage is something we're treating as a task for the future.

Also, the zone boundaries shown on the map are reference information only. Please always confirm the official zone designation and whether notification is required using the zone maps published by the Cabinet Office.

Closing

Because this system is tied to national security, plenty of people have heard the name in the news without ever actually checking a map to see where it applies. We hope this becomes something you can put to direct use in land-acquisition screening and disclosure-statement work.

Questions or feedback are always welcome at info@maprise.jp.

The important land survey area data (Watch Areas and Special Watch Areas) introduced in this post is reference information created from the Cabinet Office's "Important Land Web Map" (as of March 2026, Public Data Usage Agreement Version 1.0). It currently covers the Kyushu 7 prefectures only. Zone boundaries are reference information; please confirm official zone designations and notification requirements using the zone maps published by the Cabinet Office. For how this relates to disclosure obligations under the Building Lots and Buildings Transaction Business Act in a specific transaction, please consult a licensed real-estate transaction specialist or other qualified professional.