Zao Wou-ki's "24.2.63" will appear at Christie's upcoming spring sales in Hong Kong in May.

Zao believed only abstraction provided greatest freedom and strength. His canvases became a mesh of lines and color blocks invoking scenes of creatures from the Earth, such as ocean and fire.

He stopped naming his works after completing Cloud in 1958, only noting down the finishing date on the back of every painting.

Zao took traditional Chinese art as a reference point to create a new sense of space full of rhythm, color and light. By doing so he claimed to have rediscovered the artistic origins of China and was considered to be representative of the school of Western modern lyrical abstraction.

"People submit themselves to one tradition, while I submit to two," Zao once said of his artistic style. "Although different in presentation, realism and abstractionism are both artists' expressions toward the objective existence."

Yang Feiyun, dean of the Chinese Academy of Oil Painting, says: "Zao is undoubtedly a world-class master. His abstract painting mixes the spirit of both Chinese and Western arts - the idea, form and material come from the West, while the inner core carries the qi (essence) of oriental shan shui (mountains and waters) spirit."

Zao continued to work very hard, even in his later years. He especially loved making large-scale paintings, which required a ladder to complete. He was often so caught up in his work that he fell from the ladder several times, injuring his arm, waist and shoulder. Despite this, he never hired an assistant.

In 1985 the then 64-year-old returned to China to give a one-month painting master class at his alma mater in Hangzhou, Zhejiang province. Twenty-seven teachers and students from eight art institutions participated in the class, exceeding the planned quota of 15 people.

"He was always on time and spent a whole day in the class. And he made revisions of every student's work," recalls Zhang Xiaoming, deputy director of China Academy of Art's Oil Painting Department, who was the class monitor.

"He even let his wife be the model," adds Xiao Feng, the academy's former director.

Zao revisited the school in 2001 and 2004 to teach.

Zao's only son Jialing says his father had long hoped to build a memorial to his art in Hangzhou.

After receiving numerous awards, in 2006 Zao was made an officer of the Order of the Legion of Honor by the then French president Jacques Chirac.

The market for his work has expanded from Europe and the United States to Taiwan, Hong Kong and Southeast Asia over the past two decades. An increasing number of Chinese mainland collectors also compete for Zao's works at auction.

Leading art market watchdog Artprice.com ranks Zao 23rd in the Top 500 artists by auction revenue in 2012 and ninth among Chinese painters, in its latest report on international art market.

His painting 10.1.68 set a record in 2011 when it was sold for HK$68.98 million ($8.9 million) at Sotheby's in Hong Kong.

"I am not afraid of being old or dead," Zao once said. "As long as I can paint, I am fearless."

Li Xiang in Paris contributed to the story.

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