Japan's tiny kei cars exist because the law sets their size and engine limits
Japan's best-selling cars are shaped by a rulebook. Kei cars must fit within 3.4 metres of length, 1.48 metres of width and an engine under 660 cc, and in return owners pay less tax and insurance. By 2018, seven of the country's ten top-selling models were built to those limits.
The category dates from 1949, when few Japanese families could afford a full-size car but many could stretch to a light motorcycle. The government created a lightly taxed class for essential transport, first capped at a laughable 150 cc. Limits were loosened several times, and in 1955 the cap rose to 360 cc, making room for the Suzuki Suzulight and the 1958 Subaru 360, often seen as the first truly mass-produced kei cars. Early models could not legally exceed 40 kilometres per hour until the mid-1960s.
The Honda N360 of 1968 ignited demand, and passenger kei sales peaked at 750,000 in 1970. Then the government chipped away at the perks, added annual inspections in 1973, and tightened emissions rules. By 1975 sales had crashed to 150,000, and Honda and Mazda had quit the passenger segment. Makers argued no workable 360 cc engine could meet the new standards, so lawmakers allowed 550 cc from 1976. Most firms had guessed 500 cc and had to rush out stopgap engines; only Daihatsu had a full-size unit ready.
One famous limit is not law at all. The cap of 64 PS in power output is a gentleman's agreement among manufacturers, fixed at the rating of the strongest kei car of the time to head off a horsepower race. Similarly, the modern top speed of 140 kilometres per hour is self-imposed, partly because the cars are so narrow.
Other perks keep buyers loyal. Kei cars wear yellow number plates, and in most rural areas owners skip the certificate proving they have somewhere to park, normally required before buying a car in Japan. The class took a record 40 per cent of new car sales in 2013, and even a 50 per cent tax increase in 2014 did not dent its lead much. Few are exported, though the Suzuki Jimny, widened and given more power, has found fans abroad.
Source: Kei car
