Now, as my long-time readers know, the real, angelic (ahem) Guy In White Pajamas considers Japan a very good friend and ally of the US. However, we have now crossed over into another dimension, a dimension where the US did not invade Iraq, a dimension where realpolitik rules, a dimension where an evil, goateed Guy In Black Pyjamas controls the vertical, the horizontal, and the counterfactual.
We begin our tale in 1999, where a goateed Prime Minister Junichiro Koizumi is just comtemplating a recently passed bill making Kimigayo the official Japanese national anthem. It had been a hard road, full of silly arguments with that strain of peaceful, well-intentioned and terminally naive politicians and ad hoc people's representatives Japan had bred by the thousands since the end of The War. Yes, Kimigayo, had been the national anthem before and during the Greater East Asia War, when Japan was at its nationalistic peak, which was naturally the reason the LDP had wanted to make it official again. And Koizumi's party had ensured that the Diet had confirmed that "kimi," one of many Japanese words for "you," specifically referred to the emperor. "Kimigayo," "The Emperor's Reign," not the silly "The People's Reign" the peaceniks had wanted it to mean. 55 years, a generation of remorse, was enough.
Other laws passed over the previous decade had permitted Japanese Self-Defense Forces to operate overseas, one more step towards getting the Japanese people to accept a greater role in the world for the Japanese military. As the Japanese people saw the good the Japanese military could do, they would gradually begin to accept that the constitution must be changed. Of course, a centrally controlled education system helped. And the constitution would only be changed in seemingly small ways: get rid of the silly term "Self-Defense Forces" and give Japan an army, navy, and air force; allow Japanese troops to operate abroad under a UN mandate or to protect Japanese interests, like sea lanes; and give Japan the right to exercise collective defense. Yes, those things would be enough. How to make it all happen? Koizumi pondered long behind his mahogany desk, but nothing especially leapt to mind.
Then, after the terrorist attacks of September 11, 2001, President Bush called on Japan to stand with the US against the terrorists. How could Koizumi refuse? The entire world had seen the horror, the people jumping from the twin towers, the devastation. The US was Japan's greatest ally, and its protector. Of course Japan would stand with the US. Japanese Martime Self-Defense Forces supply ships, guarded by Japanese Aegis cruisers, ran beans, bullets, and fuel to the Coalition fleet.
Soon the Taliban fell and it was time to rebuild. New laws were passed allowing the Self-Defense Forces to serve in dangerous areas for humanitarian reasons, and 600 ground troops were dispatched to Afghanistan. Yes, the pacifists demonstrated. Yes, there were claims it was unconstitutional. Yes, Koizumi suggested changing the constitution. Clearly, the third greatest economic power in the world, a power looking for a permanent UN Security Council seat, should have a real military. It was Japan's duty. "Yes," Koizumi smiled privately. "Duty is still a big thing in Japan." The constitution was changed.
But, after Afghanistan, the US faltered, allowing the UN to take over. Then, as it increasingly looked like a quagmire, the US gradually withdrew from Afghanistan, and from an increasingly hostile world it did not seem to understand or be able to deal with. There were no more US requests for Japanese military assistance, and as US power receded, Japan looked to its own future.
With the constitution changed, the Japanese no longer needed to rely on the US to protect them. In 2010, Japan finally won it's permanent seat on the UN Security Council and increasingly stepped in to fill America's shoes in Asia. In 2012, under Prime Minister Higuchi, Japan announced it could no longer afford to rely entirely on the US to protect it from North Korea and other threats, and publicly declared its intention to join the nuclear club.
The US, weary of playing world cop, made no complaints. China, North Korea, and South Korea all wailed, moaned and threatened Armageddon would follow, but with the US 7th Fleet between them and Japan, did nothing else. There were huge demonstrations in Hiroshima and Nagasaki against the idea of Japan having nukes, to no avail. Missile subs were added to the Japanese fleet and by 2015 Japan was a nuclear power with silo-based and submarine-based nuclear weapons. Japan's new military capabilities coupled with increasing demonstrations against US bases in Japan led to the US 7th Fleet moving to Southeast Asian waters, abandoning its bases in Japan and re-establishing bases in Vietnam and the Philippines.
Finally, Higuchi mused while stroking his graying goatee, Japan's dependence on America had been ended and Japan had taken its rightful place in the world. Japan had followed America's lead in foreign affairs and put its people at risk of nuclear war by allowing US bases on its soil for decades, and the US consistently took Japan for granted, whining over Japanese car exports and other petty nonsense. Japan had kowtowed to US political wishes for decades only to be treated like third-world peasants. This was because the US knew Japan had to rely on it for defense, and knew Japan had a strong sense of indebtedness to the US. But no more.
China rose in power, but was still far behind in technology. The Europeans provided quite a bit, but there was nothing to match US-Japanese technology. Desperate to match the American hyperpower, China finally accepted Japan as a nation that would not be conquered or bullied anymore, edited its history books, and made criticizing Japan politically costly. Then it opened its gates and traded its incredibly cheap manufacturing capabilities and raw resources for Japanese technology. The exchange was very beneficial for both parties. One of China's key goals, to match US weapons technology, was nearly met, although the Japanese stubbornly refused to give China the know-how in the most recent systems, always staying a step or two ahead.
With Japanese brainpower to bring it up to speed, China quickly moved to rival the US and finally achieved junior superpower status. With China's new power, the US could no longer guarantee Taiwan's independence without risking a very costly war. Since the vast majority of Americans believed most US action abroad was at best misguided and at worst downright greedy and dangerous, Americans were reluctant to press China on the matter outside of diplomatic circles. By 2025, China had effectively isolated Taiwan and was able to threaten it, interdict trade, etc., with little repercussion outside of the occasional demarche. Taiwan clung tenuously to independence, although the world had acknowledged it was only a matter of time, probably less than five years, before it would be forced to rejoin China.
The Japanese over the years thoroughly intermingled their corporations with Chinese bureaus and corporations, ensuring that the Chinese could not hurt Japan without hurting themselves, just as the Japanese did with US corporations in the 1970s and '80s. Japanese influence, already strong in the 1990's, rose dramatically throughout Asia. Japanese and Chinese forces gradually replaced US forces in the rest of Asia as the primary stabilizers, and as other nations linked themselves to the rising dragons, an Asian renaissance blossomed.
Japan, although it shared power with China, had at last achieved its long-desired Greater East-Asia Co-Prosperity Sphere.
We now return you to your regularly scheduled universe.