Chunichi Motor Co., Ltd., Nagoya, 1950-58?
Chunichi Motor are listed in the Japanese language wikipedia site, plus I managed to find one mention of them on the Autoby web site. At the moment, I don't know how long they were in business, or how many models they made, but at least one was called the Chunichi Sankei DHa (中日サンケイDHa号). This model came with a 124cc 2 stroke engine. No doubt additional information will surface over time.