Just Type an Address, and the Official Roadside Land Price Map Opens Instantly

Hello from the MAPRISE team. This time, we're introducing a feature that lets you open the National Tax Agency's official roadside land price map (rosenka) straight from an address.

What rosenka actually is

Rosenka is the per-square-meter valuation, published every July by Japan's National Tax Agency (NTA), of land fronting major roads. It's used as the basis for valuing land when filing inheritance tax and gift tax returns, and is generally referred to as "inheritance tax rosenka" (souzokuzei rosenka). This is distinct from "property tax rosenka," a separate valuation that municipalities publish for property tax purposes.

The rosenka maps themselves are published on the NTA's website, but the base maps are actually produced by Zenrin, a mapping company. One thing worth flagging here: a rosenka map exists purely to show which road has which rosenka value assigned to it — it isn't the kind of accurately-scaled map you'd use to measure distance or area precisely. If you need the actual shape or boundaries of a parcel, you'd still need to reference something else, like a registry cadastral map or a survey plot.

Who actually uses rosenka, and for what, varies a bit by profession:

• Tax accountants and inheritance specialists: use it most directly, as the basis for valuing land in inheritance and gift tax filings
• Real-estate appraisers: use it as one reference indicator alongside official land prices and transaction comparables, to support an appraisal
• Collateral-valuation staff at financial institutions: reference it as one input for getting a rough sense of collateral property value during loan underwriting
• Lawyers and judicial scriveners: sometimes use it as a rough benchmark for land valuation during inheritance division discussions or property settlements
• Real-estate brokers: sometimes reference it alongside official land prices when considering a sale price

How this works in MAPRISE

In MAPRISE, typing an address is now all it takes to open the nearest National Tax Agency rosenka map for that location.

Search an address on the map, and a link labeled "Inheritance Tax Rosenka (National Tax Agency)" appears in the popup. Clicking it opens the rosenka map for the neighborhood containing that address, directly on the NTA's own site.

It's not unusual for a single neighborhood to span multiple rosenka map sheets. When that happens, we list all the relevant sheet numbers together and let you pick which one to open.

Clicking a link opens the actual rosenka map (a PDF) published by the National Tax Agency, in a new tab.

We're not recreating this map ourselves — this simply routes you directly to the primary source, the NTA's own page.

Rosenka gets used across a lot of different professions

As described above, rosenka isn't just for tax accountants filing inheritance tax returns. Real-estate appraisers use it in valuations, financial institutions use it in collateral assessment, lawyers and judicial scriveners use it during inheritance division discussions, and real-estate brokers use it when considering a sale price — it's a metric referenced across professions. On a given case, several of these professionals might each check the same parcel's rosenka value for their own separate purpose. We want MAPRISE to be a place where all of them can look things up on the same screen, moving between rosenka and whatever other data they need.

This is nationwide

This feature launched nationwide from day one — it isn't a Kyushu-first rollout. The National Tax Agency publishes rosenka maps for the entire country all at once, every year, and MAPRISE lets you open the corresponding rosenka map from any address, anywhere in Japan.

A little behind-the-scenes trouble

Honestly, this feature is more than just a link to the NTA's website.

The NTA's rosenka map site is built around a multi-step click flow: choose a prefecture, choose a municipality, check the index map, then open the PDF for the right sheet number. There's no clean URL structure that lets you jump directly from an address or a set of coordinates to a specific sheet's PDF. So we built logic that resolves an address (or coordinates) down to the correct prefecture, municipality, and sheet number, and constructs a link straight to the actual PDF.

The other tricky part was handling neighborhoods that span multiple rosenka sheets. Neighborhood boundaries don't necessarily line up with the map sheet grid, so depending on the address, two or three sheet numbers might plausibly apply. At first, we mechanically picked just one sheet number to show — but we realized that could mean the road you're actually looking for is drawn on a different sheet and never shows up. So we switched to listing every plausible sheet number and letting the user choose.

On top of that, rosenka gets republished for a new fiscal year every July, and the NTA's own site structure sometimes shifts slightly from year to year. We expect this to be a feature we need to keep checking on an ongoing basis, to make sure the links don't quietly break each time the fiscal year rolls over.

Closing

Opening a rosenka map just by typing an address might sound like a small thing. Even so, compressing what used to be a prefecture → municipality → sheet-number hunt down to a single click should add up to a real, steady reduction in the small time losses of everyday work.

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

The rosenka maps and assessment ratio tables introduced in this post are official information based on the National Tax Agency's "Property Assessment Standards" (base map data: Zenrin Co., Ltd.). MAPRISE simply routes you to pages published by the National Tax Agency; it does not independently calculate or guarantee rosenka values. For an official tax filing, please check the latest rosenka map and assessment details on the National Tax Agency's site and consult a tax accountant or other qualified professional.