He says dozens of the sketches on show depict a variety of insects Li painted with delicate brushwork reflect these influences, and also embody Li's understanding of the idea of "drawing the spirit and atmosphere" central to classic Chinese painting.

Before Li was able to complete epic works of a grand historic narrative such as A Picture of Flood Prevention Works in Wuhan, he traveled extensively across the country from the 1940s to the '50s to sketch.

He took several trips between 1940 and 1948 in Sichuan and Gansu provinces, as well as the Xinjiang Uygur and Inner Mongolia autonomous regions. He produced hundreds of drawings of the distinctive scenery and folk customs of West China, a selection of which are on show.

Xue says being embraced by nature motivated Li to produce more powerful, diverse strokes to render an intensity to his works, which also laid a foundation for artistic maturity he achieved a decade later.

In the 1950s and '60s, Li often traveled to the provinces of Central and South China, during which he made a large number of sketches of rural landscapes and farmers toiling in the fields. These works, some of which are also on show, presented his love for changing dawn scenes, veils of mist, night rain and winter snow.

Li Jingkun, chairman of the Guangdong Artists Association, says sketching served not only as a method of practice for Li Xiongcai but also, "an album of his travelogues and the vicissitude of life over the years by which he conveyed a humanistic spirit".

Li Jingkun says sketching allowed Li Xiongcai to evolve to become a painter "who created monumental works and raised the Lingnan school of painting and Chinese painting alike to new heights".