 War essentials exports from the United States to Japan increased by 124% along with a general increase of 41% of all exports from 1936 to 1937 when Japan invaded China.Japan's war economy was fueled by exports to the United States at over twice the rate immediately preceding the war.41.6 percent of pig iron, 59.7 percent of scrap iron and 91.2 percent of automobiles and automobile parts of Japan were imported from the United States, as Japan needed to supply huge armies some aggregating 800,000 soldiers, in China.