There are reports that China is massing troops on the North Korean border. The current explanation is plausible:
As concern mounts that North Korea will use a national commemoration on Saturday to conduct its sixth nuclear test, claims the Chinese army has amassed 150,000 troops including medical teams on the border with North Korea have been repeated on the front page of China's state-owned Global Times newspaper.
The People's Liberation Army has recently expressed concern that northern Chinese towns were at risk of nuclear pollution from North Korea's tests, and said that contamination would not be tolerated.
"Not tolerated"? Kind of an aggressive tone which is then dialed back:
China's nuclear envoy Wu Dawei met with his South Korean counterpart Kim Hong-kyun in Seoul to discuss the North Korean crisis.
South Korea's Yonhap news agency reported the two sides had agreed that if North Korea conducts another nuclear test or missile launch, China and South Korea will carry out any future United Nations Security Council resolutions that are passed.
Well, fine - the troops are there for emergency decontamination and the Chinese response will be to work more closely with the UN.
But in my fantasy, the US fires a few cruise missiles at North Korea and China responds by sending in its troops to defend its ally from imperialist aggression. And while they are there, they depose Kim Jong Un and replace him with a saner and more pliable heir to the throne, to wit, the son of the recently murdered half-brother of Kim Jong Un.
Obviously this is a long-shot. As best I recall the Chinese military has not demonstrated a particular flair for moving troops quickly - they are hostile but not especially agile or mobile, unless times have changed. On the other hand, in a year of surprises why not one more?
China's ground forces
While China commands the largest ground force in the world, it is plagued by mobility problems.
China lacks sufficient transport helicopters, and still largely relies on trains for transportation across the mainland.
The ground forces mainly exist to deter and manage conflicts with China's borders, and their goal is to increase mechanization by 2020.
The Weekly Standard covered the NoKo version of Game of Thrones.