This map shows an early proposal of post-war Japan, which would have been divided into zones of occupation much like post-war Germany. Which action had the BIGGEST impact on preventing the division of Japan seen in this proposal?

The biggest impact on preventing the division of Japan seen in this proposal was the decision by General Douglas MacArthur, the Supreme Commander for the Allied Powers, to reject the idea of dividing Japan into separate occupation zones. MacArthur believed that a unified approach to rebuilding and governing Japan would be more effective in achieving stability and peace in the region. His decision ultimately led to a more unified and coordinated effort by the Allied Powers in rebuilding Japan after World War II.