> The allies _dramatically_ underestimated the forces that the Japanese had marshalled at the two invasion sites, and it would have been not very good. They di

> The allies _dramatically_ underestimated the forces that the Japanese had marshalled at the two invasion sites, and it would have been not very good. They did not underestimate the Japanese forces. They did an assessment in early 1945 and did calculations and the needed invasion force. But the Japanese could read a map just as well as the Americans, and could guess where Olympic would happen and redeployed, which the Americans detected: * https://en.wikipedia.org/wiki/Operation_Downfall#Ground_threat https://en.wikipedia.org/wiki/Operation_Downfall#Ground_thre...