This paper surveys the history and background of how the People’s Republic of China (PRC) became one of just six countries so far to possess nuclear-powered submarines, including the core subject of nuclear reactor development and improvement across three submarine generations. If South Korea decides to pursue and successfully develops indigenous nuclear-powered submarines, it will most likely become the seventh country to do so—offering six previous paths to study, of which China is a prominent example. Three-quarters of a century after beginning initial efforts under autarkic austerity, Beijing finally has a capable and growing fleet of modern nuclear-powered attack submarines (SSNs), nuclear-powered guided-missile submarines (SSGNs), and nuclear-powered ballistic missile submarines (SSBNs) equipped with long-range submarine-launched ballistic missiles (SLBMs). What Mao sensed broadly through a geopolitical lens, modern military science shows with technical specificity: nuclear-powered submarines represent the absolute global “gold standard” for which there is no true substitute—with utterly unmatched potential in propulsion, endurance, sensor and weapons operations, and overall performance. As China’s experience shows, however, the road to success can be lengthy, expensive, and arduous. Ability to study preexisting foreign examples from afar helped somewhat, but tremendous national leadership, resources, and effort over decades have been required.