Japan-US Fuji Bicycle Co., Ltd.,, 1951-current
Japan-US Fuji Bicycle Co. Ltd. was/is a company that was set up in 1906 to market US bicycles into Japan. It still exists today as a subsiduary of Cargill and has its head office in the USA. In the post war period, a number of moped/motorcycle machines were either imported or produced locally under the Baby Runner (ベビーランナー号) and Fuji (フジ号) brands and in the first part of 1954 were sold under the Japan-US brand. In the latter part of 1954, the Baby Runner brand specifically was built and sold by a new company called Okazaki Industry Co., Ltd.
And two more Baby Runner photos from a recent displays in Japan. They appear to be two different machines as the kick starts are on different sides. I'm not sure which model year these are, or whether they were made by Japan-US Fuji Bicycle, by Okazaki or someone else completely, but for now I'll leave them here. Note the location of the carburettor.