TOKYO -- The crackdown by the Chinese People's Liberation Army 29 years ago today against student protesters was one of a series of historic events in 1989 that transformed global politics. But the tanks that crushed the democratic uprising at Beijing's Tiananmen Square also spurred changes in the relationship between China and North Korea that echo loudly in 2018.
Struggling under heavy international sanctions imposed after Tiananmen, China embarked on economic reforms to break the impasse. One piece of this puzzle involved normalizing diplomatic relations in 1992 with South Korea, the bustling economy across the Yellow Sea.
But that move rattled China's traditional partner North Korea, which believed it had a "friendship cemented in blood" since fighting side by side in the Korean War. China teaming with the enemy to the south represented a betrayal in the eyes of Pyongyang.
Sensing a threat to its security, North Korea concluded that developing nuclear weapons was the only way to ensure its survival, despite the global opposition such a move would bring. Pyongyang's nuclear program at the center of the U.S.-North Korean dialogue today is rooted in that reversal by China toward South Korea.
For a Chinese intellectual in his fifties, U.S. President Donald Trump's comments Friday reviving a June 12 summit with North Korean leader Kim Jong Un reminded him "vividly" of the events in 1989, the year that changed the world.
During the summer of 1989, this reporter was studying Chinese at a university in Dalian, a city in China's northeastern province of Liaoning. The beachside hotel in Dalian, where Kim and Chinese President Xi Jinping met in early May, was a scenic tourist spot often visited by students on excursions.
Many university students traveled to Beijing that June. Considerate railway staff let students ride trains for free, and the youngsters took the 17-hour trip to join the thousands of students who rallied around the Goddess of Democracy statue that was raised in Tiananmen Square.
Some of those students never returned. Whether they died or were arrested is unknown. It was taboo for students to talk about the fate of those who did not come back. Under pressure from the school, everyone became silent.
Later that year, the world was swept up in euphoria over the fall of the Berlin Wall. Communist regimes across the world fell like dominoes following mass protests. But China was left behind. At the university campus in Dalian, soldiers arrived as instructors in order to give communist military training to the students. Mock trenches were dug, and students trained with fake rifles as if it were a time of war.
Students were made to chant "Beware the 'Peaceful Evolution' theory" -- referring to a belief that the West sought to transform China through nonmilitary means such as democracy and freedom. Nothing scared the Chinese Communist Party more than this theory.
Just last week, the American president saw off a North Korean envoy on the White House lawn, after granting him a nearly two-hour meeting in the Oval Office. With Secretary of State Mike Pompeo by his side, Trump waved at the black sport utility vehicle carrying Kim Yong Chol, who is Kim Jong Un's right-hand man.
"We'll be meeting on June 12th in Singapore," the president told reporters on the lawn. Trump went on to discuss the Korean War. "Can you believe that we're talking about the ending of the Korean War? We're talking about 70 years," he said.
China surely cannot help but remember 1989 and the years that followed, when communist regimes fell one after another in the Soviet Union and eastern Europe. However the discussions fare between Trump and Kim Jong Un in Singapore on June 12, China needs North Korea to stay steadfastly on its side.
Having the entire Korean Peninsula under American influence represents a nightmare scenario for Beijing, which makes a U.S. guarantee of the North Korean regime's survival as important for China as for Kim himself.
China also fears that the framework for peace on the peninsula might proceed without Beijing at the table. The "Panmunjom Declaration," issued after the inter-Korean summit between Kim and South Korean President Moon Jae-in at the end of April, noted that the two sides will "actively pursue trilateral meetings involving the two Koreas and the United States" to turn the current armistice into a peace treaty as well as establish a permanent peace regime.
As if an afterthought, they added, "or quadrilateral meetings involving the two Koreas, the United States and China." But clearly, this was a secondary choice.
Moon is said to be considering participating in a trilateral summit just after the Trump-Kim meeting in Singapore, in order to declare an official end to the Korean War.
Since the Panmunjom Declaration, Beijing has pressured both North and South Korea diplomatically to pursue a quadrilateral -- rather than trilateral -- meeting, should one occur.
But the two Koreas have told China that since Beijing already has diplomatic relations with both South Korea and the U.S. -- its two enemies during the Korean War -- China technically does not need to sign a peace treaty with them. Beijing categorically denies this logic.
In this context, Beijing listened closely to Trump's words on the White House lawn, which included multiple references to China and flattery for Xi.
"I think we see a lot of very positive things happening with President Xi, who has helped me quite a bit with this," Trump said of the negotiations with North Korea.
"He's really a very wonderful guy," Trump said, but added, "He's a man that loves China, however. He wants to do what's best for China." Trump was hinting that Xi's cooperation was strictly for China's national interest, and not necessarily as a favor to the U.S.
Trump also expressed his desire that China, alongside South Korea and Japan, would help North Korea rebuild its economy with financial assistance after a deal is signed. "I think China's going to help a lot," he said.
Chinese Foreign Ministry spokeswoman Hua Chunying issued a statement following Trump's remarks, saying "we are pleased" with the progress in preparations for the summit. "Another important step has been taken along the right path of politically resolving the Korean Peninsula issue," she said.
Still, it is unclear how "pleased" Beijing will be with the outcome of the Trump-Kim summit. China, like the rest of the world, cannot achieve an accurate analysis of the situation, with Trump constantly altering his stance.
Beijing will not let down its guard, knowing that -- just like in 1989 -- the world could face historic consequences if the Korean War truly ends.
Much has changed in the past 29 years. China is much wealthier, and few Chinese students would risk their lives to stand up for democracy. But the summer of 2018 has all the ingredients to produce another geopolitical reshuffling that reshapes the world.