Brother during World War II was know as Nippon Sewing Machine Manufacturing Company in 1934. Prior to 1934 they were known as Yasui Sewing Machine Co, and was founded by Kaneschi Yasui. When the started in 1941 Nippon Sewing Machine Manufacturing Company aka Brother Sales Ltd had to switch from manufacturing commerical sewing machines to indsutrial sewing machines. Not much information was available if Brother produced any additional products for the war effort. However, it was noted that many of their factories received extensive war damage.
Epson started in 1941 as Daiwa Kogyo LTD and was located in Suwa, Nagano, Japan. Not much information was available for Daiwa Kogyo during the war effort, however Daiwa Kogyo was part of the Sieko conglomerate. Sieko like many other Japanese companies were ordered to produce military items sucn as time fuses and ammunition.
World War II and its aftermath devastated the company. Many of its factories were destroyed by Allied bombing raids, and after the war, American occupational forces tried to disband Hitachi altogether. Founder Odaira was removed from the company."