Verifying mileage and history by chassis number

The risk

Estimates in the research literature put odometer tampering at roughly 3–8% of auction sheets reaching destination markets. Japan’s auction system flags doubtful mileage on the sheet itself, but tampering after the auction, between the hammer and the export, is harder to see, and export certificates have been altered to match a rolled-back odometer.

The defence is simple and mechanical: a car’s chassis number is fixed, every auction appearance is recorded against it with the mileage on that day, and mileage can only ever increase between appearances. Any record that shows it falling is proof.

How the check works

Auction-history databases index the original sheets from the major Japanese auction houses by chassis number, going back to around 2007. A search returns every appearance: dates, grades, mileages, and the sheet images. Services of this kind cost a few dollars a report; the research brief names JP Sheet and similar providers, and the decision on this site is to embed a check like it on every car rather than rebuild one.

Read the results as a timeline. Mileage should climb, grades can move either way, and gaps between appearances should match the car’s story. A car that appeared three times in a year with three different grades is telling you something.

What to compare, and where to read it from

Four sources should agree. Read the chassis number off the physical car, from photographs of the plate and the stamping, never from the seller’s listing.

1. The chassis number on the car versus the auction sheet you were shown.
2. The auction sheet versus the auction-history record: same chassis, same date, same grade, same mileage.
3. The export certificate (deregistration certificate) mileage versus the latest auction record.
4. Any Shaken (roadworthiness) history, JEVIC or QISJ odometer certificates and service stickers versus all of the above.

Red flags

Any one of these is a reason to stop.

1. Mileage lower than at an earlier auction appearance.
2. The sheet you were sent does not appear in the database, or appears with different details.
3. Mileage flagged as unknown (走行不明) or the odometer noted as replaced.
4. Repeated auction appearances in a short period, or a grade that improved without a repair note.
5. A chassis number on the car that differs from the paperwork in any character.

After the car is registered

Once the car has an Irish registration, the Irish history services record its import status and, from then on, its NCT mileages. Keep the Japanese auction record and export certificate with the car; they are its history before it arrived, and the next buyer will ask.