Given the high level of secrecy that has long surrounded Beijing's foreign policy, diplomats and China-watchers have traditionally looked to the country's foreign affairs establishments for hints on its decision-making.
But when it come to China's policymaking towards North Korea, the large number of special-interest groups involved render such a method useless.
South Korean diplomats in Beijing privately complain that while they maintain good, effective working relations with their Chinese counterparts on various issues, consultations on North Korean-related affairs often go nowhere.
In response, Chinese diplomats argue the relationship with North Korea is a special and more complex one, and the foreign ministry has to consult a greater number of departments.
Officially, China's foreign policy is conducted through an established four-tier hierarchy.
At the top, the president heads the central leading group on foreign affairs. Then comes the premier, followed by a vice-premier (or state councillor with a foreign affairs portfolio) and finally the foreign minister.
"What I can say is that the policymaking towards North Korea is far more complicated and complex than any other area of foreign affairs," said a Chinese diplomat.
Discussions on North Korea can begin with the foreign ministry, but then go to the Communist Party, the People's Liberation Army and the party's foreign, security and ideological establishments, with the party Central Committee's International Liaison Department (ILD) acting as a mediator.
"As the main facilitator of China's relations with North Korea, the liaison office plays a central role in North Korean policymaking. The foreign ministry is an implementer of China's policy towards North Korea," said the diplomat.
For example, Wang Jiarui, the head of the ILD, paid more visits to North Korea than his government counterpart, the foreign minister.
Several recent reshuffles of staff reflect the ILD's growing prominence in North Korean policymaking. In January 2010, Beijing announced the appointment of Liu Hongcai , deputy head of the ILD, as the new Chinese ambassador to Pyongyang, replacing Liu Xiaoming , a seasoned diplomat.
"The party and the army definitely play a role in policymaking on North Korean issues," says Cai Jian , deputy director of Fudan University's Centre for Korean Studies.
This multiplicity of actors is a feature of Chinese foreign policy towards North Korea, says Stephanie Kleine-Ahlbrandt, a North Korean affairs expert and Northeast Asia project director and China adviser with the International Crisis Group.
The policy is also unlike that towards any other country in Beijing's orbit, said Dr Victor Cha, director of Asian Studies with Georgetown University and Korea Chair, Centre for Strategic and International Studies, in testimony to the US-China Economic and Security Review Commission in April 2011.
"Policy towards North Korea is not made in, nor led by, the foreign ministry ... Instead, this relationship is made, managed and protected by the liaison office of the Communist Party and by the PLA," said Cha, a former US diplomat involved in the six-party talks between China, the United States, Russia, Japan and North and South Korea on ending the North's nuclear arms programme.
"There are more actors involved in the process of policymaking on North Korea largely because of the special relations between the two nations which stem from their deep historic bond and ideological allegiance," says Professor Wang Xinsheng , a Peking University historian specialising in Northeast Asia.
Indeed, exchange visits and communications between the communist allies are usually conducted between party and military leaders rather than diplomats.
While both ruling parties share a traditional doctrine of Kremlinology, the number of mutual visits by top political leaders and the importance attached to them show the significance and priority of the relationship between the two nations.
The Communist Party and the Korean Workers' Party have an extremely close relationship and enjoy regular and high-level exchanges. From 2000 until his death in December 2011, former North Korean leader Kim Jong-il made eight visits to China. On each trip, he received treatment exceptional in comparison to that shown to any other world leader, having been met by China's nine most senior political leaders - members of the innermost sanctum of the party, the Politburo Standing Committee.
Before his death, Kim made three informal visits to China in less than 16 months, while Beijing sent top party officials Zhou Yongkang , Li Yuanchao , Zhang Dejiang and General Guo Boxiong on various occasions. All were either a member of Politburo or of its standing committee, and lacked a diplomatic portfolio. In late November, just two weeks after the party completed a once-in-a-decade power transition at its 18th congress, the new Chinese leadership sent Politburo member Li Jianguo on a visit to Pyongyang.
While Beijing claims to adhere to a principle of non-intervention in foreign policy, the Communist Party has continued to be a significant player in the Korean Workers' Party's internal affairs.
For instance, a meeting between President Hu Jintao and Kim Jong-il in August 2010 in Changchun was seen as Beijing's endorsement of Kim Jong-un as his successor at the Korean Workers' Party's congress in September that year.
Kerry Brown, executive director of the China Studies Centre at the University of Sydney, said the fact that North Korea still has a system like China's, where a Communist Party has a monopoly on power, means there is a much deeper interaction at the elite level with North Korea than with most other countries.
"For most foreign affairs issues, for instance, there would be the chair of the leading group on foreign affairs, which reportedly met very infrequently, then the state councillor and their foreign minister - who were both pretty low in protocol terms," Brown said.
Analysts said the PLA also exerts a strong influence due to the two countries' shared military history and the national security implications of North Korean policy.
In a recent speech to the US Council on Foreign Relations, Kevin Rudd, who was recently re-elected as Australia's prime minister, said the two militaries, which fought together against the United States and South Korea during the Korean war, have their own close ties.
The two armies have regular exchanges of visits through activities marking events such as the anniversaries of the entry of the Chinese People's Volunteers into the war, and of their victory.
"The Korean People's Army's historical relationship with the PLA is deep, and it's broad, and it's institutional, and it's personal, and it's cultural. And it goes back now for two-thirds of a century. So … that's one anchor point in the internal Chinese discussion on North Korea," said Rudd, who speaks Putonghua.
Cha said the PLA has historically seen the northern portion of the Korean peninsula as being critical to its security.
The recent visit to China by top North Korean envoy Vice- Marshal Choe Ryong-hae also showed the two ruling parties and armies overrode diplomatic establishments.
Choe, No3 in the Korean Workers' Party hierarchy and the military's top political officer, led a delegation of party officials and military officers to Beijing in an attempt to repair strained ties after Pyongyang's near-daily threats in March and April to wage war with Washington and Seoul.
Choe held talks with China's party chief Xi Jinping , Politburo Standing Committee member Liu Yunshan , and Wang Jiarui, as well as his Chinese counterpart, General Fan Changlong , vice-chairman of the party's Central Military Commission.
The North Korean leader may have picked Choe for his family links to the Chinese party and military, as both his parents fought against Japanese troops alongside a Chinese partisan force during Tokyo's colonial rule over the region in the first half of the 20th century, said David Tsui, a North Korean affairs expert and son of a PLA general.
Tsui, who was jailed for 11 years in China for "revealing military secrets", said the PLA helped nurture the Korean People's Army by sending up to 150,000 PLA-trained ethnic Korean soldiers in China back to North Korea in 1949, a force which formed the backbone of that army. "Some Chinese veterans might still see the Korean People's Army as a PLA affiliate," Tsui said.
Party elders and the other party's ideological establishment, such as their three main arms - the United Front, Organisation and Publicity departments - all play some role.
Brown said North Korea tended to be able to get the attention of figures such as Jia Qinglin , who was then fourth on the Politburo Standing Committee, because of his leadership of the United Front through political advisory body the Chinese People's Political Consultative Conference, and even that of Wu Bangguo , No2 on the standing committee, who, through the National People's Congress, had close links to North Korean parliamentarians.
"The trump card that North Korea always had - and will have as long as both countries have communist parties - is these strong party links. And we all know that these, in the end, are the ones that matter in [China]," Brown said.
Kim Jong-il's meeting with Jiang, the retired leader, in May 2011 explains a lot about the influence of party elders in North Korean policy. North Korea's founder Kim Il-sung also met Jiang in Yangzhou in 1991.
Other party establishments have also played their role. For instance, Zhou Yongkang , the former Politburo Standing Committee member and the party tsar on law and order, attended the military parade in Pyongyang in 2010 to celebrate the Korean Workers' Party's 65th anniversary at which Kim Jong-un made his first public appearance.
Zhou's successor Meng Jianzhu made the first public comments by a Chinese government official endorsing the North's succession plans in February 2011 when he said gave China's congratulations on "the successful solution of the issue of succession to the Korean revolution".
"The Korea war and their political alliance is a central legitimising story for the Communist Party and the PLA, as well as for the Korean Workers' Party and Korean People's Army," Tsui said.
Analysts said that President Xi Jinping , as the son of a revolutionary who has maintained close ties with the PLA and has a deep knowledge of what military policy means, might have greater clout than his predecessors Jiang and Hu to press for policy change, as he is able to mediate in reaching a consensus among various stakeholders.
Jae Ho-chung, professor of international relations and director of the programme on US-China relations at Seoul National University, said of recent reports of a shift in China's traditional policy towards North Korea that he believed Beijing's "new approach" to North Korea was more one of tactical flexibility than strategic reorientation, due to their deep historic bond.
"Though one big variable in the equation has changed with the placement of new leader Xi, it is difficult to see that as both a necessary and sufficient condition for a significant shift in China's policy towards North Korea," Chung said. Referring to a metaphor for the nations' close ties in the 1950s, Chung added: "The teeth (China) can still suffer without the lips (North Korea), whoever the leader is."