Nippon Swift Industry Co., Ltd., Tokyo, 1953?
Nippon Swift Industry was actually a bicycle company, originally starting out as a Japanese branch plant of the English Swift Bicycle company in Coventry England which was established in 1869. The Japanese company was established pre-WWII (I'm not sure when exactly, but certainly by 1933), and post WWII they produced a machine called the Royal Prince (ローヤルプリンス号), as listed in the Japanese language wikipedia site. I don't know exactly what the Royal Prince was, but I'd assume that it was some sort of moped. Both the British and the Japanese subsidiary marked their products with a stylised machine gun in the logos used on the company badges.