Actually know as kei cars in Japan, they are a (legal) category of small cars there. While the specifications have changed since its introduction in 1949, it is a car of around three meters in length. It has other limitations but they primarily apply to ICE-powered vehicles.
In the electric market, the Wuling Hongguang Mini EV is a best seller. Hundreds of thousands of them have been sold.
Other manufacturers have entered the market. The Ora Good Cat and Chery QQ Ice Cream have been on sale for some time. The newest player is is from Geometry (a mark of Geely) and is called the M2.
You may be wondering if such cars make sense outside of China. I think the answer is yes. These vehicles tend to be able to travel at highway speeds with ranges of 100 km or more. And, probably more important, they cost in the $7000 range in China. Even for $10,000 in the US or Europe, they seem like an ideal second car.