 After attending engineering school without graduating, and visiting factories around Japan to better understand Toyota's quality control processes, by 1941 Honda was able to mass-produce piston rings acceptable to Toyota, using an automated process that could employ even unskilled wartime laborers.Tōkai Seiki was placed under the control of the Ministry of Commerce and Industry (called the Ministry of Munitions after 1943) at the start of World War II, and Soichiro Honda was demoted from president to senior managing director after Toyota took a 40% stake in the company.Honda also aided the war effort by assisting other companies in automating the production of military aircraft propellers.