Kei Cars: Japan's Tiny (But Often High-Tech) Minicars

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You don't need us to tell you that the Japanese car market is about as far-removed from the U.S. market as it's possible to get.

Where big trucks still dominate in North America, vehicles that almost fit in the average truck's pickup bed make up almost half of all Japanese car sales.

Those cars are known as kei cars, or keijidōsha--"light automobiles".

Size matters

Conforming to a strict set of rules and regulations, Japan's smallest offerings started like their tiny counterparts in Europe, providing inexpensive transport in the post-war era.

But as Japan's roads became ever more crowded, their purpose shifted slightly--tight physical dimensions and small engine capacities keep size to a minimum, exempting them from Japan's rule that any larger car must have a suitable parking space. They also cut useful sums from Japan's numerous automobile taxes.

A whole industry has grown up around keijidōsha, with everything from passenger vehicles, vans and pickups all available as kei cars--even sports cars, on occasion.

Nissan DAYZ kei-class minicar

Nissan DAYZ kei-class minicar

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None are longer than 11.2 feet, wider than 4.9 ft or taller than 6.6 ft. All are limited to 660cc engine capacity, and 63 horsepower.

For comparison, a Smart Fortwo is shorter at 8.8 feet and lower at just over 5 ft tall, but wider at 5.1 ft, has a larger, 1-liter engine, and puts out 70 horsepower in U.S. specification.

Not all are as boxy as the Nissan Dayz and Mitsubishi EK Wagon you see in the video above--retro designs like the Honda N-One we drove last year are popular--but maximizing the car's exterior dimensions within the regulations ensures interior space is as large as possible. You'd be surprised how large some of these vehicles are inside.

The U.S. market kei?

Given their incredibly compact size it's no surprise such cars aren't sold in the U.S, though one vehicle gets close. The all-electric Mitsubishi 'i', or i-MiEV, is based on a kei-class car of the same name sold in several other markets around the world.

While the standard 'i' neatly meets kei regulations in terms of size (and engine capacity, in the gasoline variant), the U.S. version was widened by over 4 inches and stretched by almost a foot. This helps it meet U.S. crash regulations, and also makes it a little more suitable for the average American's larger frame than their Japanese counterpart...

1970 Honda N600 (Image: Wikimedia Commons)

1970 Honda N600 (Image: Wikimedia Commons)

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It's not the only kei-class car to have ever hit the U.S, either. Around 10,000 Subaru 360s hit the U.S. back in the 1960s, and with a larger engine for the U.S. market, Honda exported its N600 (based on the kei-class N360) in the late 1960s and early 70s.

The N600 was eventually replaced by the Civic--and with that, the rest is history.


Some kei cars were traditionally rather spartan inside and used quite basic mechanicals, but like any other vehicle these days, modern keis are remarkably high-tech.

Continuously-variable transmissions are common and in-car entertainment systems abound--you may as well keep yourself amused while stuck in endless Tokyo traffic.

Their ubiquity also makes them a popular part of Japan's tuning culture, with dedicated events and race series not unknown. At the other end of the scale, kei vans and pickups dominate Japan's light commercial vehicle industry.

Really, they're exactly as they seem--regular cars, just in miniature scale.

And while they'd struggle to sell in the U.S. among huge, imposing SUVs and trucks, they're as much a product of their environment as the Ford F-Series is in the States. But a little more fuel-efficient, too...


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Comments (7)
  1. A nice article about kei car regs, the market, new entries etc. but nothing about the actual car engine, placement, details transmission wise and most importantly...gas mileage.(diesel gas offerings?) not to mention prices safety features and possibility of imports that fulfill safety requirements.

  2. I can't speculate on the latest kei cars but have owned and run ten different types and they are a blast. You can nip through openings like a large motorcycle. I have had cars, vans, pick ups and a sports coupe and one micro motor home. Engines were water cooled two three and four cyl of 600cc to 1200cc and only for export. In the UK they would mostly return 50 to 55mpg Imp. The latest are mostly 3cyl 989cc twin cam, variable valve timing, multi valve and injected alloy units. Weights can be as low as 1650 lbs so a fantastic power to weight ratio giving very responsive acceleration and economy. My last a Daihatsu seated four six footers in comfort, had air bags elect windows A/C P/S ABS C/Locking etc etc. USA stds will prevent imports.

  3. Hi Don,

    Just to confirm - the latest aren't 989cc as that's too large for the regulations! 660cc is the limit for kei cars - a vehicle with an engine larger (like the 1300cc Daihatsu Copens sold for a while in the UK) aren't technically kei cars even though they're the right size.

  4. Antony I did say export which really refers to the last ones available here such as the Daihatsu Charade. This class has not been sold here for a few years since Daihatsu and Suzuki opted out due to low volumes and poor exchange rates. The imported UK version of the Copen was 659cc making it a Kei class until near the end when it evolved into the 1300c no doubt due to UK customer demand. The Suzuki cappuccino Kei class was always 657cc during its import run to the UK as was the Honda Beat 656cc 3 cyl and the Honda pick ups and vans. Alas none are available new today in the UK.

  5. I think the younger generation, early twenties would be happy with it, especially those living in cities. They never lived the carefree days of cheap gasoline, cheap cars and cheap everything. They never lived the passionate days of driving a fun car. They are ripe for Kei because simply enough they don't care what they drive. They only want their online experience to be as uninterrupted as little as possible.

  6. [They only want their online experience to be as uninterrupted as little as possible]
    Therein lies the answer they are shunning the car in favour of social media its called evolution plus USA safety regs will never allow this type car if they wanted it.

  7. I, too, have always been fascinated with Kei cars- or any small car, for that matter! Two kids at my high school bought brand new N600's in 1972- one of my teachers drove an Isetta (the Euro interpretation of "kei")- and you can still buy Kei trucklets for offroad use, here in the states. Unfortunately, Americans seems to have no interest in small cars, as shown by the poor sales of the Smart ForTwo and Scion IQ- which is too bad, cos these little vehicles are awesome!

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