An article by David Archibald at American Thinker. Archibald's seven reasons are:
1. Regime legitimacy. With communism dead, the current leadership's legitimacy depends on improving quality of life for the average Chinese. There is a problem, though, as Archibald explains:
China’s public debt grew from US$7 trillion in 2007 to US$28 trillion in 2014. This is on an economy of US$10 trillion per annum. A high proportion of the economic growth of the last seven years is simply construction funded by debt. The real economy is much smaller.
The Chinese government is likely to see the contracting economy and realise that issuing more debt won’t have an effect on sustaining economic activity. Thus the base-building was accelerated to allow the option of starting their war. This is a life and death matter for the elite running the party. They are betting the farm on this. If this gamble does not work out then there is likely to be a messy regime change.2. Chosen Trauma. Related to the regime's stoking of nationalism is growing anti-Japanese sentiment because the humiliation China received at the hands of Japan during the Sino-Japanese War and WWII.
3. Being Recognized as Number One. Archibald contends that Chinese pride will not allow them to willingly play second fiddle to the United States.
4. Humiliating the Neighbors. Archibald points to China's "nine-dash" claim to the South China Sea. By rigorously enforcing those claims, China can humiliate, isolate and weaken neighboring states. Singapore and Vietnam would be practically cut off if China succeeds in its claims over the South China Sea.
5. Strategic Window. Archibald suggests there is currently a certain feeling that Chinese power and ascendency is inevitable, and that this attitude could provide China a critical psychological tool in a war. But, Archibald contends, this belief in China's inevitability will evaporate if its economy implodes. Thus, China as a limited window to make use of this psychological advantage.
6. Great State Autism. By this term, Archibald is making reference to China seemingly being unaware of how much its actions alarm its neighbors.
7. President Xi Jinping. As to this point, Archibald writes:
While preparation for this war started in the 1980s, the recent ramp up in aggression has been at the direction of President Xi who, in his formative years as a party apparatchik, was impressed by how the war with Vietnam in 1979 was used to consolidate power in the politburo. President Xi has accumulated more power than any Chinese leader since Deng Xiaoping. He is using an anti-corruption campaign to purge political opponents. Chinese leaders are supposed to only rule for ten years before standing aside. Just two years into his presidency, Xi’s supporters have raised the possibility of resurrecting the position of chairman of the party (abolished by Deng to stop another Mao) so that Xi could continue to rule from that position. President Xi is a nasty piece of work who has been toughened up by his life experiences. At the age of 15, he was sent to live and work with peasants in the yellow earth country after his father was purged. His accommodation was a cave. His stepsister suicided due to his father’s oppression by the Red Guards.Archibald then discusses Japanese fears of Chinese aggression and the United State's interests in keeping the sea lanes open (which objective is directly impacted by Chinese claims to the South China Sea).
The seventh reason is probably more important than any other single factor. It seems clear that the influence of particular leaders is a critical factor in whether a country goes to war. WWI was not inevitable, but because many important leaders wanted war, there was war. WWII was not inevitable. The French and British certainly didn't want to go to war. The German army was opposed to war. It is unlikely Stalin wanted war (certainly the Soviet Union was ill-prepared for war). But Hitler wanted war. Similarly, a showdown between great powers now would probably require a leader who was insistent on war.
In any event, Archibald's article concludes with his view of the general theaters of operations and how an initial attack by China might go down. Read the whole thing.