The nationwide used car dealer, Gulliver, recently set up a new venture called Gulliver Minicle, which deals only in kei-jidosha, often referred to as minicars in English, though here we like to call them K-cars, which make up a separate class of automobile. The engine displacement can't be more than 660cc, and they were developed in the '60s and '70s for people with limited incomes.
When K-cars first appeared the engines were as small as 360cc, and have always been a point of contention for the U.S. automobile industry, which describes them as a "non-tariff trade barrier" because taxes for K-cars have been much less than they are for regular cars and thus are deemed as being unfair competition for infamously larger American cars — though it should be noted that U.S. automakers have tried to sell compacts in Japan.
K-cars have always had one glaring drawback. Because the engine is so small, they have to be light, and that means they are less safe. Consequently, families don't buy them; or, at least, they didn't until recently.