 Japan quickly lost 93 percent of its oil supply after President Franklin D. Roosevelt issued an executive order on 26 July 1941 which froze all of Japan's U.S. assets and embargoed all oil exports to Japan.In addition, the Dutch government in exile, at the urging of the Allies and with the support of Queen Wilhelmina, broke its economic treaty with Japan and joined the embargo in August.Japan's military and economic reserves included only a year and a half's worth of oil.