content: Maybe because America in the 60s had a huge cold war ICBM program that they wanted to fund, and one day someone said "these stupid rockets are useless for anything other than to nuke the USSR... wtf are we gonna use them for, to go to the moon?" and everyone said "bob! you're a genius!" Meanwhile Japan has had no military rocketry R&D going on and they have zero space industry. So yeah, from nothing to a moon rocket in 13 years isn't bad. I mean, SpaceX has taken longer than that to get to the point where they're looking at sending a lunar orbiter.