Ever since Pearl Harbor the drive to defeat the Japanese in Tokyo was end goal for every American with no other consideration. In spring 1945 the warring nations believed that the United States and Allies would be invading the Japanese Home Islands, especially with the collapsing war with Germany. Anyone looking at a map would know this would be nothing like assaulting Normandy. There would be no England for a staging area some 30 miles away and now everything would have to come by ship to the conflict.
American military had basically two invasion concepts, one invading Japan itself and the other invading opposite China area for staging against Japan. Eventually the decision was made to assault Japan in a two-phase approach. OPERATION OLYMPIC was the first in assaulting lower Kyushu Island to secure an operational staging area and commence OPERATION CORONET on Honshu of the mainland. Follow-on estimates would involve over 815,000 combatants for OLYMPIC and 1.4 million for CORONET. These are significantly greater than Normandy with 156,000 combatants. Further, with the increasing casualty rates when going closer to Japan, they estimated over 400,000 casualties for OLYMPIC alone.
It was easy for the Japanese to assume the same in their defense, and they were prepared with using over 8 million local citizens and military in the area. The intent was to inflict as great a bloodbath as possible for the United States to become war-weary and negotiate a peaceful war end, as done in WW I. The Japanese would have effectively won what they went to war for, retain the Emperor, most likely retain desired captured countries, and sustain the military-ruled government.
Yet there were a few direct peace attempts from both sides during the spring and summer that progressed enough to be finally ignored by senior officials because of distrust for the enemy. The stumbling block between the two nations was "unconditional surrender" established by Roosevelt. Knowing what befell Mussolini and Hitler, the Japanese mindset was frozen in keeping their God-like Emperor. There was going to be an invasion.
In the United States there were less than 200 people that knew about and were developing atomic bomb designs, and all the rest involved were relegated to very limited knowledge operations that read indicators, machined parts, turned valves, and the like. During final bomb development, diligent discussions were convened at the highest levels to determine actual bomb use as an alternative to invasion casualties. American losses would be limited to several B-29 crews and not the estimated least 400,000 casualties. Without logical opposition, Truman made the decision to use atomic bombs as first act and invasion second.
X-DAY is historically accurate until the dropped bombs do not explode, due to a logical condition. From thereon the story continues with complete American offensive and Japanese defensive plans detailed and gathered from numerous actual sources. The book is full of trivia most never heard about, detailed maps by MacArthur's teams, Kyushu's assault beaches, numerous personnel and weaponry tables, and data. Further, for both sides prevailing actual political, military, and natural events that happened to impact warfare and resulting decisions. The invasion happens not as actually planned and more extreme surprises beyond expectations occur for both sides. Logically the conflict is resolved.
