Not for style, this is why Japanese kei car number plates are not placed in the middle

Balance and symmetry are what make some people sane. Yet, there are moments when one would feel that something is not right when seeing something off-balance like an uneven tile arrangement, a bottle cap that’s not screwed properly or why most kei cars have their front number plate not positioned in the centre.

Think about it, whenever you see a Japanese kei car, the front number plate is often placed on the right side and not in the middle like most cars in general. Still, there are a few non-Japanese cars that have their number plate holders placed off-centre in the name of style such as the Alfa Romeo 147 and 156.

While the cutesy-looking kei cars look like they have a single toothy grin, there is a form in their placement and it is not just for show.

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The reason for this off-looking design is because of the constraints and regulations of what can be considered a kei car. Aside from the engine size (up to 660-cc) and power output (no more than 64 PS), kei cars also have strict dimensions.

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In order to qualify as a kei car, it must be no longer than 3,400 mm in length, 1,480 mm in width, and 2,000 mm in height. With all that tiny size, designers and engineers are limited in terms of how much engine room they can put in. Add on with the fact that there needs to be some cabin space inside and you might notice why they all look like minibars with four wheels.

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But back to the engine bay and with such limited size and space, the designers and engineers face a challenge in fitting in the powertrains and other essential components in a diminutive compartment.

For example, the radiator which is normally placed behind the front grille would instead be placed closer to the transmission.

Take a look at the photo of the Honda N-Box’s engine bay above. Notice that thanks to the small size, every mechanical component is placed in a compact and tight space and that there is no room for the radiator to be placed in front of the engine like a normal car.

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This is where the awkwardly placed number plate comes into play. Since the smaller radiator is placed closer to the transmission, which is at the side rather than in the centre, the number plate would have to be placed on the other extreme end instead of the middle for better air flow into the engine.

Besides, the oil filter on kei cars is also usually placed behind the number plate so even changing it doesn’t require much of a hassle as mechanic-san only has to unscrew the number plate holder to access it.

It’s no wonder that some people are fascinated by kei cars. It’s more than just a cute-looking vehicle or an affordable means of travel in Japan, it’s an engineering marvel and many modern kei cars also have tonnes of safety features.

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However, with the growing trend of EVs, even kei cars can’t escape the transition to an electric-powered era. Since a kei EV wouldn’t need a radiator as there is no cooling involved, let alone an engine, perhaps the days of off-centred number plates would be gone, much to the delight of the OCDs.

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