At the time, the students in Tiananmen Square could not have known how their protest dramatically shifted the delicate balance of power inside the Communist party.
"The students were not aware of the all the political infighting behind the scenes," said Zhang Gang, one of the heads of a key government institute that provided Mr Zhao with ideas for reform.
"There were so many groups trying to kill each other. What the students wanted at the time was totally rational. They wanted more justice in society and that is a normal request.
"But I cannot fully endorse their protest on the streets because it made the balance of power suddenly shift. Zhao Ziyang had so many enemies and it gave the hardliners the ammunition to attack him. Of course, I agree even less with how the Party responded."
Mr Zhang claimed that the conservatives had tried to depose Mr Zhao at an annual Party meeting at the beach resort of Beidaihe in 1988.
"These kinds of power struggles were common under Mao and we thought they had gone away after the Cultural Revolution but actually they were still there under the surface," he said.
Mr Zhao's downfall was a key moment in the run-up to the bloody massacre in Beijing on June 4. A day after the two leaders visited the students, Mr Li signed the order for martial law in the capital.
For Mr Zhang, the end of Mr Zhao's reign at the top of the Communist party derailed what could have been China's glasnost, instead ushering in an era of unmatched economic success but ever-tighter political control.
In the run-up to the tumult of 1989, Mr Zhao had fostered a group of 120 young and idealistic researchers to help draw a map for China's future. "It was only Zhao Ziyang and his aide Bao Tong who wanted to listen to young people. The rest of the party were just old men," said Mr Zhang.
"We had all been through the Cultural Revolution and we wanted to make a better future. All that mattered to us were the ideas. Not theoretical ideas, but real ideas, based on research, that could be put into practice to improve the country," he said.
One of his former colleagues, Wang Hui, remembered that the group had managed to block a plan in 1986 by conservatives to bolster the central planning system.
"We felt it was urgent to push on with contracts and shareholdings for businesses to help them make a profit. In the end, the top leaders listened to us," he said.
In March 1988, they produced a pioneering piece of research to show how to support proper business contracts. "We found over half of the 1600 business disputes we analysed were due to a lack of respect for contracts," said Mr Wang. "Zhao Ziyang said our report was very inspiring."
However, Mr Zhao's proteges found themselves attacked from all sides. "The conservatives thought our push to open China up to the world and to have a free market was bourgeois," said Mr Zhang. "The students and the intellectuals thought we were not going far enough!"
"The old Red revolutionaries hated us," remembered Mr Wang. "They thought it was better to starve to death than move away from Communism. But they were not able to debate with us over policy, so they simply kept accusing us of being capitalists or of being spies for the United States."
At one point, Mr Wang said, the group was accused of being affiliated to the CIA because George Soros had funded some of their overseas study trips.
In the end, the demise of Mr Zhao and the quashing of the protest movement spelled disaster for the group.
"I remember getting a phone call on the night of May 16 saying that Zhao Ziyang had been removed [from power]. On May 19 we had a meeting. Some said we should stay silent, but I argued that we should tell people what our mission was before we were shut down," said Mr Zhang.
After publishing a statement exposing the fighting inside the Party, around 20 people were put in prison. Mr Zhang fled first to the United States and now lives in Macau. Mr Wang continues to live in the US.
Some of the others brought together by Mr Zhao's call for reform have gone on to scale the heights of the Party, however. One large meeting of idealistic youths, which took place in the hill-top retreat of Moganshan in the early 1980s, was attended by Wang Qishan, now a member of the Politburo Standing Committee.
"Some members of that Moganshan group are now provincial leaders, or at minister level, or even in the Politburo," said Mr Zhang.
"They have not changed the way they think, they are still sticking to the hope they can make chances, but the reason they act differently is the system.
"They have always been aware of China's problems, and in private they speak frankly. But the reality of politics is you cannot just say what you think, you have to wait for the right moment, when the balance of different powers changes," he added.
Additional reporting by Adam Wu