Yu Guangyuan, a renowned economist who helped late paramount leader Deng Xiaoping launch his market reforms in late 1970s, died yesterday. He was 98. Yu, who also once advised liberal former party chiefs Hu Yaobang and Zhao Ziyang , co-wrote a keynote speech delivered by Deng at a crucial party meeting in 1978. Deng's speech to the Third Plenum of the Communist Party's 11th Central Committee that year is seen as heralding the era of market reform and openness. The plenum is now remembered as a watershed in modern Chinese political history. "Yu was one of the most liberal party officials and influential economists in the late 1970s and 1980s," said political affairs analyst Chen Ziming . Chen said Yu's would also be remembered for proposing to the leadership that it reverse its verdict on the mass protests in Tiananmen Square in 1976. Yu made his proposal in an important internal meeting of the party's Central Committee in 1978, suggesting the leadership reconsider their verdict on the so-called April 5 Tiananmen incident, which was held in memory of Deng's patron, the late premier Zhou Enlai , but turned into a protest against the extreme leftist rule of the "Gang of Four". Deng was accused of masterminding the protest and was ousted by the Gang of Four, who were later purged themselves. Yu was also reprimanded shortly after the June 4 military crackdown in 1989 for having sided with Zhao during the student-led movement. Overseas Chinese media reports suggest that Yu and three other liberal party elders only retained their party membership thanks to the protection and the influence of the chairman of the Central Advisory Commission, Chen Yun . Yu, Du Runsheng , Li Rui and Li Chang were all members of the commission, a body of retired party leaders who were consulted on main policy matters. Chen Ziming, who was a leader of the 1989 pro-democracy protest, said Yu penned an article expressing his admiration and sympathy for the students in the liberal Economic Weekly, even after martial law was declared. Born in Shanghai in July 1915, Yu studied at Tsinghua University then went to Yanan to join the communists in 1937, before war against the Japanese.