Be it landscapes, birds, flowers or figures, Qi's paintings are high on expression and detail, Wu says. He is also known for his seal carvings, poems and for setting art school trends.

Qi was prolific even in his 70s. In a group of paintings that are now on show, Qi drew some insects in the corners, leaving parts of the images blank. According to Lyu Xiao, another researcher at the Beijing Fine Art Academy, Qi did so because he wanted to fill in the parts later while focusing on the finer details first, before his eyesight became weaker.

"He had planned to fill these spaces with flowers later on, when he thought he wouldn't see as clearly as he did while painting the insects," Lyu explains.

After New China was founded in 1949, Qi was widely hailed as a "people's artist".

Wang Yamin, curator of the ongoing exhibition, says: "He was not only diligent, but also had a taste that was close to the grassroots."

A native of Xiangtan, Hunan province, Qi used to be a carpenter. He first learned painting from folk artists and later sold paintings for a living in Shanghai and Beijing during the period of great social upheaval in the country. That was also a time when he met some influential painters. Such life experiences made him understand different social strata, rather than catering to only high tastes.

Among his other paintings exhibited are flowers with blessings for prosperity, vegetables indicating harvests and farming tools to express his nostalgia for his hometown.

"People love these paintings because they remind us of the mountains and waters in the countryside, and remind us where we come from," Wang says.