Japanese VIN decoder

Japanese-market cars carry a chassis number, 車台番号, on the frame or body. Japanese Wikipedia's page on 車台番号 describes the usual form for a car built and sold in Japan: the type designation, a hyphen, then a five to seven-digit manufacturing number. Its own example is SX31-9000001, where SX31 is the vehicle type and the part after the hyphen is the manufacturing number.

日本のメーカーが生産・販売する日本国内向け車両の場合は型式に続けてハイフンと5ケタから7ケタの製造番号を組み合わせて表すことが多い。例えば、「SX31-9000001」と表記されている場合は、SX31が車両の型式で、ハイフンの後は製造番号である。

The same page keeps the two identifiers apart. The 17-character number standardised in North America is a vehicle identification number (車両識別番号); Japanese makers' export vehicles carry that instead. A car sold new in Japan is read by its chassis number.

A full model designation can carry a prefix before the code. Japanese Wikipedia's article on 自動車排出ガス規制 says each emissions regulation has its own identifier, attached before the vehicle type designation with a hyphen.

各規制ごとに識別記号があり、車両型式（かたしき）の前にハイフン（-）を伴って付与される。

So the prefix tells you which emissions rules the car was certified under. The page does not present a prefix as a model year, so do not read a year from it alone. The register keeps the prefixed forms it has seen on each code row as aliases, for example E-JZX100 and GF-JZX100 on the JZX100 row.

The part after the hyphen is the manufacturing number. Japanese Wikipedia's page on 車台番号 describes it as a serial and gives no rule by which the number yields a date, so the chassis number alone does not tell you the build month.

The build date is recorded separately. On the inspection certificate (自動車検査証), the first-registration month (初度登録年月) is the month the car first received plates and first entered the registration file, and Japanese Wikipedia's page on the certificate notes that on cars that took time to ship or sat in a storage yard, the first registration can be far from the year of manufacture.

輸送に時間の掛かる輸入車や、モータープールでの長期在庫車などでは製造年次と大きくかけ離れる事もあり、アメリカ車などモデルイヤー制によるVIN表示を行なっている車両の表示とは必ずしも合致しない事がある。

For cars first registered from 2006, the same page says the date of manufacture is stored in the inspection certificate's outer QR code, separate from the chassis number.

Read the build month off the car's own plate or its records, then run that month through Is it US legal yet?, which counts the 25 years from the date you enter. General information only: eligibility is decided by that car's date of manufacture.

The register reads JZX100 as a Toyota Mark II / Chaser / Cresta, recorded as built Sep 1996 to Jun 2001 in Japan, with medium confidence. The JZX100 code page carries the sources for both dates and the US eligibility line, and the eligibility check takes the build month from the car's plate.

• The chassis code register: every Japanese code with its production start and end, a confidence level and a source for each date. One page per high-demand code goes deeper, and one page per make lists the rest.
• Is it US legal yet?: the decoder hands the code over; you add the build month from the plate and the tool counts the 25-year NHTSA line and the 21-year EPA line.
• Landed cost: once a car clears the age lines, duty, fees, freight and registration, line by line, with a source for every rate.