The Korea Central News Agency (KCNA) reported on November 2 that Xi Jinping, General Secretary of the Communist Party of China (CPC) Central Committee, sent a reply to North Korean leader Kim Jong-un's congratulatory message on the success of the 19th CPC National Congress. The Xi-Kim exchanges suggest that party-to-party and state-to-state relationships between China and North Korea have held the bottom line, despite the fallout from Pyongyang's insistence on developing nuclear weapons. This is a positive signal to both countries and to the whole region.
Many have speculated that North Korea was highly likely to conduct new nuclear or missile activities during the Congress. But this did not happen. Pyongyang sent a congratulatory message to Beijing as is the tradition between socialist countries, and Beijing responded with courtesy. 
China and North Korea have traditional friendly ties. Sustaining and developing such a friendly relationship is fully justified. But serious disputes over the Pyongyang nuclear issue are a bare fact, and this tests the Sino-North Korean friendly relationship.
The issue has fallen into a pattern that is full of challenges, and the role China plays in it is particularly tricky. China is a neighbor and the largest trading partner of North Korea, the country that suffers the most in strategic security from the Pyongyang nuclear issue, the main mediator in the crisis, and a supporter and the main implementer of the UN sanctions. Such a sophisticated role determines that China is the most active in promoting a peaceful solution to the crisis.
North Korea feels deeply insecure. As a result, it develops nuclear weapons and intercontinental ballistic missiles despite all the risks, and expects the international community to eventually give in due to the concerns over the potential escalation of tensions. In response, the US intends to coerce North Korea to yield, and is pushing the sanctions on Pyongyang to the extreme. It has even increased the threats of war against North Korea given the less-than-expected effects of the sanctions.
Washington's and Pyongyang's strategy of "deter" and "coerce" has had no effect in addressing the problem so far, except for pushing the situation into the direction of conflict, which neither expects. 
Generally speaking, the US has strength advantages, and thus is still attempting to simply exert more pressure on North Korea. Many analysts from Washington believe that US President Donald Trump's upcoming Asia tour will further pressure Pyongyang. 
But we hope that during his visit, Trump can learn more about the rationality of the China-proposed "suspension for suspension" and "dual track approach." These two proposals are the most realistic, least risky starting points that could lead to denuclearizing the peninsula. Given the serious divergences between Washington and Seoul on the use of force, and the contradictory statements by US officials, China's proposals consider the maximum interests for all, and are likely to be the only choice to address the crisis.
The complexity of the nuclear crisis means that all sides may have to make some concessions to reach a peaceful solution. China is playing the most difficult role in the process, and is the real hope of peacefully addressing the crisis. Neither side should press China in an extreme way.