Best Japanese Kei cars

Kei cars, designed to meet strict size and power requirements to take advantage of Japanese rules that encourage small cars, are cool; we profile some great ones

There is an interesting debate to be had about whether strict rules stifle or encourage creativity.

The natural argument is that the more rules there are, the less freedom there is for expression. Counterintuitively, though, having to work around difficult regulations can produce intense innovation, catalysing original ideas that would not otherwise have existed.

Take Kei cars: designed to meet legislative requirements surrounding power, engine size and physical dimensions, qualifying cars benefit from reduced sales and road taxes in Japan, while also not requiring “garage certificates” that prove their owners have space to park them – something larger vehicles require.

Despite the rules these vehicles have to meet being strict, Japanese manufacturers have designed everything from Kei people carriers and pickup trucks, to vans and sporty roadsters.

Here, we pick some of our favourites.

What do Kei regulations require?

Short for keijidōsha, or ‘light automobile’, Kei cars at one point made up 40% of the Japanese new-car market, although a reduction of incentives in 2014 saw their popularity diminish somewhat.

Kei-car rules have changed over time, but currently mandate:

Engine: no more than 660cc (0.66 litres)
Power: limited to 64hp
Dimensions: under 3.39m (L), 1,48m (W), 2m (H)

1. Honda S660 (2015-22)

You only need to look at the S660 to see why we’ve included it. A two-seat, mid-engined roadster, the S600 replaced the Honda Beat and had such a well-balanced chassis it could reportedly have handled twice its 64hp output, despite its small dimensions.

With excellent 45/55 weight distribution and tipping the scales at just 850kg, the S660 would rev all the way to 7,700rpm, – though we’d wager this is more enjoyable if you specified the six-speed manual version rather than the CVT automatic.

2. Daihatsu Copen (2002-12)

The second-generation Copen came along in 2014, but we’ve opted to include the original here partly as it’s design is neater, and partly because unlike most Kei cars, this one was actually officially imported and sold in the UK.

At the time, folding metal hardtops were all the rage, popularised by cars like the Mercedes SLK and the Peugeot 206CC. And while that trend may have abated now, the fact Daihatsu’s engineers were able to fit such a contraption into so small a car earns it a place on our list.

3. Autozam AZ-1 (1992-94)

Built by Mazda under its Autozam sub-brand, the AZ-1 was inspired by a Suzuki design and was, like the Honda S660, a mid-engined, rear-wheel-drive sports car.

Unlike the S660, though, the AZ-1 had Ferrari Testarossa-inspired side strakes, and gull-wing doors – reason enough for an entry in our rundown. Despite being sold for only two years, the AZ-1 remains an iconic Kei car, and is fondly remembered by enthusiasts.

4. Honda N Box (2017-present)

The Honda N-Box minivan is one of Japan’s best-selling cars, and is arguably the polar opposite to the S660’s take on the Kei-car format.

The N-Box can be had with both front and four-wheel drive, while despite its restricted dimensions it offers impressive practicality, with individually sliding rear seats, the ability to carry a wheelchair, and front seats that can be turned into a bed. Oh, and it does all this while looking pretty darn neat.

5. Suzuki Mighty Boy (1983-88)

We won’t pretend that the Mighty Boy is an objectively good vehicle – with just 28hp, a titchy load-bed and no four-wheel drive, it certainly has less practicality than might reasonably be expected from a pickup truck.

Yet nonetheless there’s something appealing about a shrunken utility vehicle. While the Mighty Boy may not have been a huge success (while Kei flatbed vans are relatively established, the Mighty Boy is the only pick-up), God loves a trier.

6. Caterham Seven 160 (2021-present)

Kei cars are designed to meet regulations that only apply in Japan, so it’s hardly surprising that 99.99% of these vehicles are built by Japanese car companies.

The Caterham 170 is one of only two non-Japanese Kei cars we know of (the other being an adapted Smart ForTwo), and features a 660cc Suzuki engine, weighing at a frankly absurdly light 440kg.

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