Kogaku Industry Co., Ltd. (Shimura-machi, Itabashi-ku, Tokyo), 1957-59
Koken Kogyo KK (Itabashi-ku, Tokyo) ?
I get two different translations of the company name and also have found two different company names, but the machine brand is Koken (コーケン) as seen on the tank badge. In 1958 they produced a range of machines including clip-on moped units up to a 125cc machine. Engines were sourced from several suppliers. Yaplog has a full page showing their 1958 model line-up at this link. At this point I have no data suggesting they continued past 1959.