Japan keeps a stockpile of the necessary material. Just in case. It is perhaps China’s greatest nightmare: a nuclear-armed Japan. Permanently anchored off the Asian mainland, bristling with nuclear weapons, a nuclear Japan would make China’s security situation much more complex than it is now, and force China to revise both its nuclear doctrine and increase its nuclear arsenal. To be perfectly clear, Japan has no intention of building nuclear weapons. In fact, it has a strong aversion to nukes, having been the only country to actually be on the receiving end of a nuclear strike on its cities. Japan’s strategic situation would have to grow very dire for it to undertake such a drastic and expensive option.