Konosuke's career continued to advance at the Osaka Electric Light Company as he was quickly promoted to higher paying positions, until, at the age of 22, he became an inspector - the highest post a technician could hope for.
Earlier, Konosuke had tried in vain to interest his supervisor in an improved electrical socket he had designed and built in his spare time. Now, dissatisfied by his job's lack of challenge, Konosuke's thoughts returned to the socket once again.
Remembering his father's advice about the advantages of being an entrepreneur, he left the security of his well-paid job on June 15, 1917 to set up his own small manufacturing company.
Konosuke's savings totaled less than 100 yen, scarcely enough for basic tools and supplies - power tools were, of course, out of the question. However, undaunted by his meager resources, he set up a shop in his tiny dirt-floored tenement with two co-workers from Osaka Electric Light Company and Mumeno's youngest brother, Toshio.
Sales of the socket were poor, and by the end of 1917, Konosuke's former co-workers pulled out, leaving only Konosuke, Mumeno and Toshio.
Mumeno's pawnshop register tells the story of months of hand-to-mouth survival.
On the brink of bankruptcy, the company was saved by an unexpected order for a thousand insulator plates for electric fans.