While I agree on almost all of this (frubals my good man), I would note that the omission of international influence and non regional military assets in the east china sea is a rather significant one.
At the same time, the russian angle is one that should be given more note when we examine the potential for a major international conflict. Russia like china is frequently constrained by western powers and is having western military assets moved into location in nations along their border. Like China has had their attempts to secure resources stymied by western powers (just as has happened in reverse). Russia is just as likely to be a player in WWIII as china (indeed if it happens sooner then Russia is MORE likely that china whereas if it happens later china is more likely). Though both are likely to get involved when you consider how close their economic and military efforts have been in recent years.
With this backdrop, Japan as you mentioned and the often overlooked India emerge as vital regional powers. Were either of these two to ally with Russia and China, the resulting block would likely eclipse those that have historically sought to obstruct them. This would particularly be so were they able to convince Japan, but tbh I believe that less likely than to convince India.
Africa, the Arctic, the Middle East and the South China Sea, are all potential triggers for WWIII if we are to assume that Russia or China are to be parties to this war; one that would likely result from the current cold war like climate of geo-political positioning and economic influences. When put that way, it IS possible that an event like Syria could precipitate a wider conflict in theory. However the time is not yet right for those that might seek to prevent the furthering of western influence in the middle east.
And to be brutally honest, even if western nations are in WW3 they may not even be central players in the conflict (it could be russia vs china vs india for example) if we continue our current trends in terms of economic mismanagement, reduced industrial competence and rampant consumerism, we have made our nations both poorer and less able to support themselves (two very different things).
*Sorry, it's gonna be a wall of text again*
You brought up several good points, Arctic sea situation being one of them. In that case too, Russia's role is prominent. But, perhaps because of this precisely, a very different chance also exists: that in case of an Far-Eastern war, Russia would stay out. Think about it. They are recovering from soviet collapse, they have plenty of growth opportunities and a great competitor from China. They would have plenty of gain from skipping ww3 in far-east, as in post-war scenario they would emerge as a superpower again.
China (PRC) is the one powerhouse that has plenty of valid, historically pattern-proven reasons to ignite war:
- It holds grudges against Japan for A) history B) territory C) envy.
- It holds a monopoly on rare-earth trade (95% of world total).
- It has economic growth required to support military campaign of that magnitude (7% annual GDP growth).
- It has the industrial might required to replenish inevitable losses.
- It has the military might of all three branches: an extensive naval force, world's 2nd largest, recently modernized, and stealth-capable air force - and up to seven million troops (paramilitaries included).
- It has strong motives: reconquest of Taiwan island and 'reunification of Chinas', a rallying point for nationalist sentiment; defense of maritime borders in South China Sea, mainly against ROC and Philippines; backing its buffer state North Korea in time of crisis.
- All of its potential enemies are allies of United States, which increases its interference in the region.
- Mindset: it may sound weak as an argument, but its quite serious. China has been a laugh stock in power politics, driving China to a situation where it has a lot to prove in order to be taken seriously. Not only this, but the so-called "Patriotic Education", propaganda aimed at children, will result in population willing to fiercely defend their country against scorning. In addition, China has the identity of being the greatest culture in the world history - being a laugh stock is starkly in contrast with that identity. It is very frustrating to the nationalist elements within PRC.
- China has the ability to bring United States' economy to its knees, in theory. No other country has this ability.
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Hatred, anxiety and resentment towards Japan.
I cannot stress this one enough. More often than not, wars are sequels to previous wars. This would mark 3rd major war between China and modern Japan within time frame of 150 years - not to mention how Taiwan/ROC is tied directly to the events of two previous Sino-Japanese wars, and to Japan's colonial policy. Japan's re-armanment is a question of life and death for many Chinese people. To them it looks like Imperial Japan is making its return, and last time when that happened with Meiji era imperial restoration, smaller Japanese military handed China's butt over to it. The historical context is dark and sinister. Also, Japan is pushing out some heavy hardware, referring to the new Izumo class carrier and her to-be-built sister ship.
Mark my words, its gonna be a Korean war all over again - with extension to Japan, ROC, NATO, Philippines (with additional possibilities: India's angle on Tibet, India-Pakistan relations, Russia's far east plans with their Mistral class deployments to Pacific; role of Indonesia, Singapore, Thailand and Vietnam?).