This article incorporates information from the equivalent article on the Japanese Wikipedia.
2008 Suzuki Wagon R Stingray 01

The Suzuki Wagon R, the best selling kei car in Japan since 2003.

Kei cars, K-cars, or keijidōsha (軽自動車?, lit. "light automobile") (pronounced [keːdʑidoːɕa]), are a Japanese category of small vehicles, including passenger cars, vans, and pickup trucks. They are designed to exploit local tax and insurance regulations, and in most rural areas are exempted from the requirement to certify that adequate parking is available for the vehicle.[1][2][3] This especially advantaged class of cars was developed to promote popular motorisation in the post war era. While successful at home, the genre is generally too specialized and too small to be profitable in export markets.[4]

Kei car registration plate
Japanese black on yellow license plate Japanese yellow on black license plate
Private car Commercial vehicle


The cars feature yellow licence plates, earning them the name "yellow-plate cars" (black numbers on yellow background for private use and yellow numbers on black background for commercial use) in English and Spanish-speaking circles.[2][3] Because regulations only restrict physical size and engine displacement (and latterly outright power), manufacturers have been able to introduce many advanced technologies to the class. As a result, kei cars are often available with forced induction engines, automatic and CVT transmissions, front-, rear- and four-wheel drive, hybrid drivetrains, air conditioning, GPS and many other features.[3]

Daihatsu, Honda, Mitsubishi, Subaru, and Suzuki all manufacture kei cars, while Nissan sells badge-engineered Mitsubishi and Suzuki models,[5] and Mazda offers badge-engineered Suzuki models. Smart[3] offered a kei version of their Smart fortwo, the only non-Japanese manufacturer to have sold a car there which fulfills the Kei standards.


360 cc eraEdit

These standards originated in the times following the end of the Second World War, when most Japanese could not afford a full-sized car yet had enough to buy a motorcycle. To promote the growth of the car industry, as well as to offer an alternative delivery method to small business and shop owners, kei car standards were created.[1] Originally limited to a mere 150 cc (100 cc for two-strokes) in 1949, dimensions and engine size limitations were gradually increased (in 1950, 1951, and 1955) to tempt more manufacturers to produce kei cars. It wasn't until the 1955 change to 360 cc as the upper limit for two-strokes as well as four-strokes that the class really began taking off, with cars from Suzuki (Suzulight) and then Subaru finally able to fill people's need for basic transportation without being too severely compromised.

The class then went through a period of ever increasing sophistication,[6] with an automatic transmission appearing in the Honda N360 in August 1968, with front disc brakes becoming available on a number of sporting kei cars, beginning with the Honda Z GS of January 1970.[7] Power outputs also kept climbing, reaching a peak in the 40 PS (29 kW) Daihatsu Fellow Max SS of July 1970.[8] Sales increased steadily, reaching a peak of 750,000 in 1970. Throughout the 1970s the government kept whittling away at the benefits offered to kei vehicles, which combined with ever stricter emissions standards to lower sales drastically through the first half of the decade.[6] Honda and Mazda withdrew from the contracting passenger kei car market, in 1974 and 1976 respectively, although they both maintained an offering of commercial vehicles.

Until 31 December 1974, Kei cars used smaller license plates than regular cars (230 x 125 mm). As of 1975, Kei cars received the medium sized standard plates (330 x 165 mm).

550 cc eraEdit

Sales had been steadily declining, reaching a low water mark of 150,000 passenger kei cars in 1975. The even stricter emissions standards which were to be introduced in 1975 proved problematic for kei manufacturers, in particular for Daihatsu and Suzuki who focused on two-stroke engines. Tiny Suzuki was worst off, with their entire production consisting of two-stroke engined kei cars.[9] Daihatsu also had the engineering backing of their large owner Toyota. All manufacturers of kei cars were clamoring for relaxing the dimension requirements, claiming that the emissions standards could not be met with a 360 cc engine (even though Subaru's SEEC-T equipped Rex proved it possible). The Japanese legislature relented, increasing the overall length and width restrictions by 200 mm and 100 mm respectively. Engine size was increased to 550 cc from January 1, 1976.[9] Most manufacturers had expected a 500 cc limit and had already developed engines to fit this limit, and these were quickly introduced along with widened bodies. These interim versions (ranging between 443 and 490 cc) only lasted for a model year or so, until manufacturers had had time to develop "full-size" engines.

History of regulationsEdit

Date Maximum length Maximum width Maximum height Maximum displacement Maximum power
four-stroke two-stroke
8 July 1949 2.8 m (9.2 ft) 1 m (3.3 ft) 2 m (6.6 ft) 150 cc 100 cc n/a
26 July 1950 3 m (9.8 ft) 1.3 m (4.3 ft) 300 cc 200 cc
16 August 1951 360 cc 240 cc
4 April 1955 360 cc
1 January 1976 3.2 m (10.5 ft) 1.4 m (4.6 ft) 550 cc
March, 1990 3.3 m (10.8 ft) 660 cc 47 kW (64 PS/63 hp)
1 October 1998 3.4 m (11.2 ft) 1.48 m (4.9 ft)

Financial AdvantagesEdit

  • Vehicle excise tax
Taxable amount is only 3% of the purchase price, compared to 5% for a regular sized car.
  • Automobile weight tax
For a three year period, the amount is 13,200 yen. For two years it costs 8,800 yen, which compares to the 18,900 and 12,600 yen respectively charged to larger size passenger cars. The savings are thus above 30% in both cases. This weight tax is paid after the vehicle has passed its safety inspection.
  • Automobile liability insurance (compulsory insurance) premiums
A 24-month insurance contract typically costs 18,980 yen at the time of registration, versus 22,470 yen for a regular car.
  • Optional added insurance is also much cheaper.

Financial DisadvantagesEdit

Due to the popularity of "light cars" there is a tax on the size of these vehicles called the Light Motor Vehicle Tax. The amount charged for the size of "Passenger Cars" (the largest of the three classifications recognized in Japan) is 7,200 yen (83.5USD), or 4,000 yen (46.4USD) for commercial vehicles. Normally the car tax on "light cars" below 1,000 cc is 29,500 yen (342USD), with passenger cars and trucks with a load carrying capacity of 1,000 kg or less is at 13,200 yen (153USD). (Some local governments may charge even higher based on local regulations).



After World War II, Kei car was born as the public car. The engineers of the erstwhile Nakajima Aircraft Company developed the first truly successful Kei car, the Subaru 360.


The Kei sports car was born by "Bubble boom" in the latter years of the 1980's, although a few sporty iterations such as the Fronte Coupé and Minica Skipper had appeared in the early seventies.


The engine capacity has been expanded to 660 cc to aid high-speed performance and the increased weight of new safety equipment, which has also necessitated a slightly larger body.

Commercial vehicleEdit

A lot of kei trucks ("keitora") and microvans are used in Japan. The price of many of them is one million yen or less.


  1. 1.0 1.1 "Minicars: Cheap and Cheerful", Peter Nunn, JAMA, January-February 2005
  2. 2.0 2.1 "Owning a Car in Japan", ALTs in Sendai
  3. 3.0 3.1 3.2 3.3 "Small Things in Good Packages", Jerry Garrett, New York Times, November 25, 2007
  4. Rees, p. 79 Microcar
  5. "Nissan Adds Third Minicar to its Lineup in Japan",, June 6, 2005
  6. 6.0 6.1 Rees, p. 78 Microcar
  7. Nippon Kei Car Memorial, p. 79 Nippon
  8. Nippon Kei Car Memorial, p. 75 Nippon
  9. 9.0 9.1


^  (2007) 360cc: Nippon 軽自動車 Memorial 1950→1975 (in Japanese). Tokyo: Yaesu Publishing. ISBN 978-4-86144-083-0. 
^ Rees, Chris (1995). Microcar Mania. Minster Lovell & New Yatt, Oxfordshire, UK: Bookmarque Publishing. ISBN 1-870519-18-3. 

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