Eikyu Internal Combustion Engine Industry Co., Ltd., Nagoya, 1953
Eikyu Internal Combustion Engine is listed in the Japanese language wikipedia site. In 1953 it is listed as producing one machine called the Eikyu (or Eku) Baby Sumita (栄久式ベビースミタ号) which most probably was a moped. While I haven't been able to locate an example of the machine, I have been able to find a reference to the company's post WWII efforts, as in 1948 it produced a wood burning gas generator for use in powering stationary engines. It is refereneced on page 134 of the document entitled "Basic structure of Japanese automobile substitute fuel technology history" (本邦自動車用代用燃料技術史の基本構造) written by Shigeki Sakagami (坂上茂樹) in 2018 at the Osaka City University. Alternate fuel sources were required due to severe fuel shortages in the immediate post war time period.