Digging Up a Property’s Original Building Permit Records

The first time I pulled a building permit file at my local ward office, I discovered that the second-floor addition on a property I was about to buy had never been legally registered. That single sheet of paper saved me from a purchase that could have cost me an estimated 2,800,000 yen in retroactive fines and a partial demolition order. After 15 years of buying, renovating, and self-managing 9 rental properties across Japan, digging up the original kenchiku kakunin (building confirmation) records is now one of the very first things I do before I sign a purchase agreement, not after.

Most buyers skip this step because it feels bureaucratic and slow, and honestly, it is slow. But when I finally went back and checked the paper trail on all 9 of my properties, 3 of them had some kind of undocumented work that the seller either did not know about or chose not to mention. One was a converted garage. One was an enclosed balcony that pushed the building past its allowed floor area ratio. The third was a small rental unit built directly on top of a required 50cm setback line.

Why the Original Permit Record Matters More Than the Listing Sheet

A real estate listing sheet tells you the floor plan, the age, and the asking price. It does not tell you whether the building standing in front of you actually matches what the city approved decades ago. In Japan, a legally built structure needs a kakunin zumi shomeisho (confirmation certificate) issued before construction and, ideally, a kensa zumi shomeisho (completion inspection certificate) issued afterward. If the physical building does not match those two documents, you are not just buying a house, you are buying someone else’s unresolved compliance problem. I have also noticed banks getting stricter about this at loan appraisal time over the last few years, so a mismatch can quietly kill your financing before you even find out why. On a refinance I attempted 3 years ago, the appraiser flagged a 6 square meter discrepancy between the registered floor plan and the actual building, and the loan stalled for almost 2 months while I sorted out the paperwork.

Where the Records Are Actually Kept

The original confirmation application is filed with the local municipal building department, or with a private kenchiku kakunin kensa kikan (a designated confirmation agency) if the builder used one instead of going through the city directly. For most houses built before roughly 1998, I expect the city office to hold the file. For many built after that, a private agency may hold it instead, though the city counter can usually point you to the right one. I call ahead, bring the registered address and lot number (chiban), and ask for a copy of the daicho, the ledger record of the property’s building history. Retrieval usually costs around 300 yen per copy and takes anywhere from same-day service to about 2 weeks, depending on how old the file is and how well that particular office has archived its records.

What You Will Find Inside the File

Once the file comes back, it typically includes several distinct documents, and I go through each one line by line against the current building:

• The kakunin zumi shomeisho, proving the design was approved before construction started
• The kensa zumi shomeisho, proving an inspector actually signed off on the finished building
• The original floor plans and elevation drawings, useful for comparing against today’s layout
• A structural calculation summary, required for buildings over 2 stories or above a certain size
• The site plan showing legal setback lines, road access width, and the building coverage ratio used in the original approval

Red Flags I Have Learned to Watch For

On one property built in 1987, I measured the current floor area at roughly 18% larger than what the original drawings showed, which meant a previous owner had enclosed a veranda without ever filing a change of use application. On another property, there was no kensa zumi shomeisho in the file at all, meaning the building had never passed final inspection even though it had been rented out to tenants for over 20 years. In my experience, missing inspection certificates show up far more often on houses built in the 1970s and 1980s than most first-time buyers expect, simply because enforcement was looser back then. I now keep a simple checklist taped inside my property binder for every new purchase, and I walk the actual building against the drawings room by room before I let a deal close.

What To Do When the Records Are Missing

Sometimes the file really is gone. City offices in Japan are not required to preserve every paper record forever, and older archives do get thinned out over time. When that happens, I hire a kenchikushi (licensed architect) to do a physical survey of the building and compare it against whatever partial records still exist, usually for about 100,000 to 150,000 yen. Finding unauthorized work does not automatically mean walking away from a deal. Instead, I use the finding to renegotiate the price, since bringing an addition into full compliance can run anywhere from 500,000 yen for paperwork-only corrections up to several million yen if structural changes are required.

I would rather spend 2 weeks and a few thousand yen chasing down old paperwork than spend a year fighting the city over a violation I inherited without ever knowing it existed. That is the approach I use across all 9 of my properties, and it has kept every single one of them fully compliant and easy to finance.

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