Kanto Auto Works Co., Ltd., Tokyo, 1953-60
Kanto Auto produced a line of small 2 stroke machines ranging from 90cc through to 200cc under the Kanto (カントー号) brand name. Like many other small companies, they were an 'assembler' and used engines from several manufacturers.
The tank badges in some of the ads shows 'Kanto Jidosha Co. Ltd' on the 200cc, and 'Kanto Shoko Co. Ltd.' on the 125cc. Kanto previously traded under the name Kanto Commerce and Industry Co., Ltd. (関東商工株式会社). Yaplog shows them as being in business since 1953 so I've used this as a starting point although other texts show 1957, possibly because of the company change of names. The company name on the later ads and in sources elsewhere translates as I've shown in the title. That change of name also probably accounts for why 'Shoko' appears in some of the ads and Jidosha in others (pre and post 1957 ad material).