Operation DOWNFALL, the invasion of Japan, was in two components scheduled for the Fall and Spring of 1945-46:
Operation OLYMPIC, Nov 1, 1945, after the hurricane season, before winter. General Krueger, Sixth Army, with nine divisions (3 more in reserve) was to invade three beaches in southern Kyushu, the southern-most of the four Japanese home islands. This was to became a giant airbase to support the next invasion phase in the Spring of 1946. The Japanese had correctly predicted our invasion point and had reinforced Kyushu threefold over initial US expectations.
Operation CORONET, March 1, 1946, of Honshu, the main island, with 22 divisions in the Spring after air fields on Kyushu allowed landbased air support. There were to be two prongs:
General Hodges, with the 1st Army to land east of Tokyo, clear the peninsula, establish air fields, land tank divisions transferred from European, about 30 days, then charge across the plains to take the capital.
Ten days after the initial landing, LtGen Eichelberger with 8th Army was to attack west of Yokohama, Tokyo's seaport, open Tokyo Bay and block any reinforcement of Tokyo.