there is a common misconception that japan can made ICBM imidiantely if the law allows it, that's not true, you don't have the tech netheir the resources, basically it need money and a comprehensive industrial system to provide everything you need then takes decades to accomplish it and another decades to optimize, a country like japan can not offer the money even you can offered it, decades of reaserching such thing is extremely dangerous, when your action got exposed to the international community it's the end of the game. nuclear submarine is out of question, never think about it.
Giving technology and dollars to China? You are so funny, do the Japanese always think that Americans are all fools? Maybe there is, but those elite leaders with German blood and Jews are definitely not. The potential opponent of the United States is China. American politicians realized it as early as the 20th century on the North Korean battlefield, but because of the world of capital, capitalists need cheap labor, It's not that they are kind and it's not that they are stupid!