China's strategy is in a state of flux right now, as they are adjusting to the reality that their decade-long doctrine that the US was declining is simply no longer believable and that Beijing is not, in fact, the center of the reborn Sinocentric Order the NPC imagined.
The one making a desperate play, in my opinion, is North Korea.
Kim has never trusted China, and this distrust was fanned into a flame by some of Xi's casual remarks that hinted at a belief that "reunification of the Motherland" included annexation of North Korea.
To that end, he has been trying to break his dependency on China. That, more than anything else, is what the Trump/Kim summit in Singapore was about. It was Kim showing China "I can switch sides if I have to." The US is probably aware that North Korea is putting out feelers for that, but the problem is neither the US nor North Korea really trusts each other that much. Also, Japan doesn't trust North Korea a bit, and the US has only just regained Japan's trust after betraying them in 1972 with the Kissinger Communique, and embracing North Korea would be the straw that broke the back of the US-Japan alliance, so even though we might be willing to put aside Human Rights issues and even overlook NK's nuclear program if they were pointed at China instead of us (let's be clear; Kim has no intention of disarming), we can't afford to because we can't lose Japan.
The best thing the US could do right now, geopolitically speaking, would be to keep talking tough-but-not-too-tough, and play a sort of good cop/bad cop on North Korea, with South Korea as the good cop to our bad cop. Let South Korea make peace with North Korea, while we make sure South Korea still finds us a better ally than China. North Korea's closer ties with South Korea as they develop, coupled with their distrust of China, will pull them into the arms of their southern neighbor, even if not so much that neighbor's ally (the US).
That way, the US won't lose our alliance with Japan because we will not have handed NK the keys to the kingdom, and common interests (concerns over Chinese and Russian influence in the region, economic development) will be enough to maintain peace, albeit not friendship, between Japan and the two Koreas.
If Japan, the US and the Koreas can manage that tapdance without one of them making a misstep (which will basically be a question of "do all sides understand that's the plan"), then the Korean peninsula will be on the road, albeit a long one, toward reunification without giving Japan cause to panic (they have the capacity to become a military power again if they feel threatened) or the US cause to come sweeping in with guns blazing. The only one to lose out will be China, who is soon going to be too busy with internal problems to care.