 The relationships Honda cultivated with personnel at Toyota, Nakajima Aircraft Company and the Imperial Japanese Navy would be instrumental in the postwar period.A US B-29 bomber attack destroyed Tōkai Seiki's Yamashita plant in 1944, and the Itawa plant collapsed on 13 January 1945 Mikawa earthquake.Soichiro Honda sold the salvageable remains of the company to Toyota after the war for ¥450,000 and used the proceeds to found the Honda Technical Research Institute in October 1946.