This information was used as an important part of war efforts. It was noted that this was a considerable contribution to Germany's defeat. Historians have said this reduced the war effort by at least two years, some say four years - a clear example of how mathematicians controlled information and how it was used as a great weapon of war . The devastation caused by the atomic explosion in Hiroshima in 1945 gave rise to images that remain forever etched in the public's mind, and rightly so. Calling this war the “physicists’ war” is not incorrect in this regard. However, information, and mathematicians' obtaining that information, was clearly a large part of the world war.