Tokyo's citizens felt secure eventho at war; Radio Tokyo assured the people they and Emperor Hirohito were safe from enemy attacks.
Kamikaze mystique constituted a spiritual fortress around the Japanese homeland. No foreign attackers since Kublai Khan 1281 when a violent storm had turned him back; this storm called kamikaze or divine wind.
During the previous 4 ½ months their armed forces had scored triumph after triumph (including assaults on American territories of Guam, Philippines and Hawaii) on the war fronts of the Pacific; victory fever reigns.
A US submariner named Capt. Francis Low had seen aircraft taking off from the USS Hornet in Norfolk, Va; watched Navy aircraft practicing take-offs and landings on runways painted like flight decks; then he noticed twin engine army bombers overhead on a mock bombing run - what if Army bombers could take off from an aircraft carrier? US commanders dared not attempt a carrier attack against Japan using short-range Navy aircraft b/c would be detected and attacked b4 launch point but Army bombers had much more range and could possible catch Japanese defenders with their guard down.
Idea goes onto Navy Adm who wrote it out and it was passed on the Gen Arnold who chose Col. James Doolittle aged 45 as the to get the men and aircraft together for the mission, NOT fly it but plan it - he had too much know how to be risked on a combat mission.
Why Doolittle? Flying fame only 2nd the Lindberg, set aviation speed records, had performed the 1st outside loop, scored a first in blind flying', earned a doctorate of aeronautical science from MIT, in general if it had wings and looked like a plane - chances were good Doolittle had either flown or could fly it.
B-25s chosen could take off but they were too large to land on carrier so this was a 1 way mission so landings would be in either China or Russia; Doolittle estimates success at 50-50.
Vladivostok 1st choice of landing spot but Stalin was already dealing with the Germans and didn't want to PO the Japanese so Marshall and Arnold forcefully ask Chiang Kai-shek for landing permission, Chiang Kai-shek reluctantly agrees.