Japan also had experimental jet fighter which might have been used against an invasion force to great sucess perhaps. How do you use an atomic bomb "tactically"? Anyways if Japan would have been invaded, who knows what would have happened? We'll have to assume nukes weren't used to destroy almost every city. Kamikazes would have killed thousands. Tens of thousands would have been killed from the bottomless Japenese pool of soldiers. Millions of civillians of every age would have attack American soldiers, most likely with bambo spears. Hundreds of kamikaze subs and torpedoes would have sunk hospital ships, ammunition ships and troop ships. Under the wait of ten thousand kamikazes, experimental jets, kamikaze torpedoes, kamikaze rockets and kamikaze subs, who knows what would have remained of the invasion force? Hell Japan could have used biological weapons against LA and San fransisco. They had submarine aircraft carriers, at that point they could use their biological weapons against the major cities of the west coast. In the end we probably would have won, but Japan might have never recovered. Tens of millions would have died defending their Emperor. In the ends of millions of casulties might have been taken among the soldiers and sailors. Large amounts of civillians in LA and San Fransisco could have died...