After long providing a protective umbrella for North Korea, China has changed its stance. Beijing was supportive in passing the United Nations’ sanction resolution against North Korea and has been active in enforcing the trade embargo.
A few of the events that happened in June this year demonstrated China’s position.
Lee Yong-soo, the Vice chairman of the Workers’ Party of the Democratic People’s Republic of Korea (DPRK) visited China in early June. Since Lee expressed, during his meeting with Xi Jinping, that North Korea would continue its nuclear development efforts, the visit was not very fruitful. Xi has been pushing for denuclearization in the Korean Peninsula.
A few days later, China arrested a North Korean spy who was stationed in Dandong City, a city on China’s border with North Korea. He was a high-ranking official in the spy network and referred to as “representative of the home country” and “General Manager” for smuggling embargoed materials from China into North Korea. China also expelled two other Pyongyang spies.
Then on June 14, China’s Ministry of Commerce, along with the Ministry of Industry and Information Technology, the Atomic Energy Authority, and the General Administration of Customs, published a list for an embargo against North Korea. The list contained “items and technologies that can be used to produce weapons of mass destruction and/or its delivery vehicles.”
Has China really made a dramatic change in its North Korean policy?
The answer is yes. This policy shift can largely be attributed to the in-fighting between Xi Jinping and Jiang Zemin’s faction.
Jiang Zemin was the Chinese Communist Party (CCP) head from 1989 to 2002. He built up a large faction. Even after he “retired” from the post of top leader, he and his faction still effectively controlled many areas in China. As a result, Jiang’s successor, Hu Jintao, had limited power during his term from 2002 to 2012.
The next leader, Xi Jinping, took office in 2012. Xi learned some lessons from Hu. He fought against Jiang’s faction in order to take power back into his own hands. Over the past three and a half years, Xi has used anti-corruption charges to take down many of Jiang’s loyalists.
Over the years, Xi has consolidated power in many areas, including the military, security, law enforcement, the provinces, and foreign policy.
The cool down of the Sino-DPRK relationship is a reflection of the end of the policies of Jiang’s faction and the start of Xi’s policies.
The Jiang faction’s North Korean policy was based on two premises: One, China and the DPRK are only two of a few communist countries left in the world. China therefore wanted to support its “red” brother. Two, they wanted to use North Korea as a pawn in their game with the U.S.
There was a report that an informant of Qian Qichen, former Vice Premier in charge of foreign affairs, disclosed to the U.S. that North Korea did not previously have nuclear weapon capability. Beijing set up its nuclear capability to create a threat to the U.S. It wanted to use this threat to counter U.S. support for Taiwan, or even force the U.S. to give up its support. The Six-Party Talks over North Korea’s nuclear development was just a never-ending show. 
In the past few years, as Xi has gradually taken over foreign affairs, he has moved to establish a different agenda.
Xi seems to care less about the communist ideology and more about other things, such as traditional Chinese culture and the “China dream.” After he took power, the first country he visited on the Korean Peninsula was South Korea, not China’s long-term “brother,” North Korea.
Also, the North Korea nuclear situation is getting out of control. It seems that Kim Jong-un is not so obedient and is determined to build the capabilities of his country’s nuclear weapons and missiles. This has become not only a threat to the U.S. and its allies, but also a potential danger to China as well. As the Chinese idiom goes, China has “raised a tiger; now it faces the danger.”
Besides, Xi seems to prefer an open approach instead of dirty tricks. For example, he promised the U.S. and has since made good progress on his promise to stop the cyber intrusions which, when Jiang’s faction was in power, had exploded into constant, massive attacks on the Western government and on businesses.
Xi has distanced Beijing from Pyongyang and has been advocating the denuclearization of the Korean Peninsula.
We can compare the Jiang Faction’s interactions with North Korea with Xi’s to observe the sharp policy changes.
Close ties with Jiang’s faction
In March 2001, when Zeng Qinghong, Jiang’s right-hand man, visited North Korea, Kim Jong-Il offered him a warm reception and even issued a sheet of stamps with the picture of Kim and Zeng on it.
Zhou Yongkang, another heavyweight in Jiang’s faction, visited North Korea from October 9 to 11, 2010, for the 65th anniversary of the Workers’ Party. He sat next to Kim during the military parade. More importantly, he held four meetings with Kim Jong-Il during the three-day visit.
When North Korea conducted its third nuclear test on February 12, 2013, China reported that it would support the United Nations’ sanction against North Korea, but it would not cut the supply of food and fuel to North Korea. China supplied 80 percent of North Korea’s oil imports, part of which was to power its army and tanks. China-DPRK Friendship Oil Company under the China Petroleum Pipeline Bureau conducted China’s oil exports. As the head of the “Oil Faction” (a group of officials with a background of working in the oil industry), Zhou Yongkang was suspected to be behind supplying oil to North Korea.
There is a report that Zhou leaked the secret discussion between Hu Jintao and Jang Sung-taek, Kim Jong-un’s uncle and once the number two person in Pyongyang. Jang, during his visit to China, had a secret meeting with Hu to discuss the possibility of replacing Kim Jong-un with his brother Kim Jong-nam who stayed in China. Hu only listened and didn’t give an opinion. Later Jang was suddenly arrested and killed. A “deep throat” from North Korea, who escaped to China, informed Beijing that Zhou had leaked the conversation.
When Zhou was taken down in China, one of the official investigations was into his “intentionally leaking national secrets.”
Xi Jinping proposed Vice President Li Yuanchao to lead the Chinese delegation to North Korea for its 70th anniversary of the Worker’s Party in October 2015, but Kim Jong-un rejected Li. Instead, he asked for Liu Yunshan, a Politburo Standing Committee member and a loyalist in Jiang’s faction.
Liu led a large team from Chinese Central Television (CCTV) to North Korea. They recorded and broadcasted the military parade live.
Liu also arranged the visit of the North Korea music troupe to Beijing in December 2015, to soothe the relationship between the two countries.
Cool down by Xi Jinping
The China Institute of International Studies (CIIS), a think tank affiliated with China’s foreign ministry, republished an article on March 14, 2016, stating Beijing’s policy change. “[Over time,] the China-DPRK relationship gradually lost the ‘ally’ characteristic. China and the DPRK naturally changed from ‘Mutual Assistance Allies’ to ‘Friendly Neighbors.’ In the 21st century, the Chinese government defined relations between the two countries as the normal relationship between two countries, which was an acknowledgement of the current status.” 
In July 2014, Xi Jinping visited South Korea. This is the first time that the top Chinese leader visited Seoul without having first visited Pyongyang.
On September 3, 2015, at Xi’s high profile military parade to celebrate the 70th anniversary victory day of World War II, South Korean President Park Geun-hye was a distinctive guest, standing next to Xi Jinping. Choe Ryong-hae, a senior North Korean official dispatched as Kim Jong-un’s personal representative, was refused even a brief meeting with Xi Jinping.
In December 2015, North Korea announced that it had developed a hydrogen bomb. At the same time, Moranbong Band, a North Korean music troupe, whose visit Liu Yunshan had arranged, arrived at Beijing to give two performances. However, during the rehearsal, Chinese officials noticed that the stage backdrop had images of North Korean missile launching scenes. China requested that North Korea remove the images. Kim Jong-un refused to do so. The performance was cancelled and the troupe went back to North Korea.
This year, China repeated its discussions about denuclearizing the Korean Peninsula and worked with the U.S. at the United Nations to pass the sanction bill against North Korea.
On May 6, 2016, Kim Jong-un held the Seventh Congress of the Workers’ Party to showcase the unity of the party and his total control over the country. A few state heads sent congratulatory letters to Kim, but Xi Jinping didn’t. Instead, Beijing sent a letter from the CCP Central Committee. The letter was relatively plain. It congratulated the Workers’ Party but didn’t mention Kim Jong-un’s name at all.
Pyongyang remained cold in response to the letter. A Chinese netizen posted a message, “Kim is such a character. The Korean Central News Agency announced right away when they received the congratulatory letters from the Cuba Communist Party and the Nicaraguan Communist Party, but even by May 7, it still had not mentioned China’s letter. Late?”
Pyongyang didn’t invite Beijing’s delegation to attend its congress either. At its Sixth Workers’ Party congress in 1980, Li Xiannian, then Vice President of China had led the Chinese delegation to the event. Hua Guofeng, then top leader of China sent Kim Il-sung a congratulatory letter.
So clearly, after gaining power over foreign policy, Xi is steering the boat of China-North Korean relations in a totally different direction.