TOKYO -- The president of a country once called Tianchao, Heavenly Dynasty, last month greeted the leader of one of its former tributary states. It was Chinese President Xi Jinping receiving North Korean leader Kim Jong Un.

That was the storyline that the Chinese state media wanted to portray, and North Korea was happy to play along. China's state-run Xinhua News Agency said that during the summit Xi referred to Kim as ni, while Kim referred to Xi as nin. Both pronouns mean "you," but nin is more polite and respectful than ni.

In customary tributary-system fashion, the leader of China showered the visitor from Pyongyang with expensive gifts.

How expensive?

At a banquet in the Great Hall of the People, Xi and Kim toasted with glasses of an extraordinarily high-end maotai.

Maotai is a type of baijiu that is also known as moutai, and the rare vintage bottles are the envy of all baijiu lovers. The "white liquor" -- the direct translation of baiju -- was produced in the 1960s and 1970s, years that cover the Cultural Revolution.

The high-alcohol-content tipple is a staple of state dinners. Its makers say maotai wards off dementia and inspires poets.

A waiter is seen holding brown bottles of baijiu at the dinner between Xi and Kim. © Reuters

But the extra-fine stuff is rare. On a leading Chinese shopping site, the type of maotai served at the banquet, those kept in brown bottles with red rubber caps, sell for 1.28 million yuan ($203,000) a piece.

On the afternoon of March 27, when it was time to return home, Kim boarded a dark green train with a yellow stripe at the Beijing Railway Station. The so-called "No. 1 Train" is used only by the reigning Kim, and is reportedly designed to be difficult for U.S. spy satellites to detect.

Still, it was odd that the young North Korean leader chose to go by rail.

Kim once studied in Switzerland and has traveled by air many times. The world had expected him to make his first foreign trip as leader by airplane, thus presenting himself as a new-generation head of state. His father and grandfather were known for their hatred of air travel.

Two sources familiar with Sino-North Korean relations explained why Kim took the family train to Beijing.

"To be sure," the first source said, "ensuring his security was an important reason why Kim came to Beijing using the traditional, long and special train. But another reason was that the train can carry more and heavier cargo than an airplane."

The train that was reportedly designed to elude detection by U.S. spy satellites can be seen behind a high-speed train at the Beijing Railway Station on March 27, 2018. © Reuters

The train linked together 21 cars when it left the Beijing Railway Station. The cars were loaded with large quantities of luxury items, including a number of bottles of that high-end maotai.

"The use of the train shows how serious the shortage of some luxury goods is in North Korea, partly due to a lack of foreign currency."

According to the second source, luxury goods are a tool that Kim uses, like his father before him, to keep his subordinates loyal.

China's gifts to the North Korean leader included at least six bottles of vintage maotai, as well as many other nonvintage bottles of the spirit.

"In addition to maotai," the source said, "the gifts Kim received in Beijing probably included premium whisky, foreign luxury brand goods like watches as well as cigarettes and various other products. It has become difficult for Kim to obtain luxuries due to international sanctions. And North Korean leaders have made a tradition out of bestowing designer merchandise to special senior officials to buy their allegiance."

North Korean state television aired a long documentary about Kim's visit to Beijing that showed presents being exchanged between the two countries, including the vintage bottles.

The extent of Xi's generosity earned some online scorn in China. One netizen summed up his rage with an insult and a series of questions. "Kim Fatty III turned against China," the post began. "Why do we have to use our money to treat him to ultraluxury maotai and present him with various luxury goods? Do we really have to do this while we have an anti-corruption campaign banning lavish spending?"

The government's censors were quick to erase the dissent.

These are bottles of simply expensive maotai. The bottles of the ultra expensive type are brown, not white. © Reuters

But Kim received something besides tangible gifts. It was China's backing as he heads into a meeting with U.S. President Donald Trump in May. This was more valuable than any of the items loaded on the train.

"Kim saw that the relationship between the U.S. and China was deteriorating quickly in both political and economic terms, and saw an opportunity to drive a wedge between them," said a source knowledgeable about the Beijing-Pyongyang relationship. "Kim probably has no intention of giving up his nuclear weapons."

Indeed, ever since the Xi-Kim meeting, the U.S. and China have been bogged down in a tit-for-tat trade war over tariffs.

Another source said that with China's backing, "Kim may try to buy time and further develop North Korea's nuclear weapons."

After the summit, a short fictional account of the Xi-Kim summit went viral among Chinese internet users:

Handing gift after gift to Kim, Xi thanks the North Korean leader for being polite and respectful, allowing him to save face. Xi apologizes for the heavy restrictions on Chinese exports to North Korea and asks Kim a question:

"You talked about a phased denuclearization during our talks. How long do you intend to keep this going?"

To this, Kim replies with a wink. "But of course, until Trump steps down."

Kim offers to talk in more detail when Xi visits Pyongyang.

Chinese censors took the story down. While only a comic account, the tale does capture some elements of the picture. Reportedly, during the summit, Xi actually did accept an invitation from Kim to visit North Korea at a convenient time.

This image taken from North Korea's Korean Central News Agency shows Xi Jinping and Kim Jong Un walking by honor guards in Beijing. KCNA said Kim was walking slightly ahead of Xi. (KCNA/Reuters)

For Xi, the meeting with Kim was necessary to dispel the notion that China has been left in the cold on the Korean Peninsula issue.

But there was more on Xi's mind than looking like a big brother figure. Although he has reinserted himself into Korean Peninsula politics, Xi remains concerned that Trump and Kim might strike a "grand bargain" that could alter the power balance in Northeast Asia.

If North Korea were to align itself with the U.S. to contain China's rise in Asia, the geopolitical power game would enter a new dimension. In this scenario, Kim would be dusting off an old Chinese war secret: Yuan jiao jin gong, to befriend a distant country to attack a neighbor.

Yuan jiao jin gong is the 23rd secret art of war in "Thirty-Six Stratagems," a military playbook that dates back to China's Three Kingdoms period (A.D. 220-280).

The ancient land of Qin, before establishing a dynasty, learned first hand the effectiveness of teaming up with lands far away. The king's first inclination was to attack the distant Qi, but he was advised that making war on Qi would require travel through neighbors Han and Wei, and that it would be better to befriend Qi and another distant land, Chu. The attack, the adviser suggested, should instead be against Qin's neighbors.

The king acted on the advice, attacked Han and Wei and eventually built an empire that would include the lands of his former allies.

So while Xi and Kim exchanged smiles, handshakes and gifts, trust between the two nations has hardly been restored. The first U.S.- North Korea summit, now still in planning stages, has the potential to be a significant game changer.