The exhibition pairs pen drawings, which Zhu sketched outdoors and mostly in monochromatic ink, with Chinese ink-color paintings which he completed based on the drawings.

The pen drawings show Zhu's attention to details, vividly presenting them with precision, refinement and a neat manner. The pieces are done in the classical Chinese painting style of gongbi zhongcai (meticulous brushwork and heavy colors), which requires accurate depiction of the subjects and strong color tones. Zhu is acknowledged as a master of this style.

Du, who studied under Zhu's guidance at Tsinghua, says: "The quality of tools and materials used does not determine the value of an artwork. Simple items can also produce works of high quality. Zhu's pen drawings are a good example of this."

Zhu Heng, a grandchild of Zhu Danian, says his approach to art was to create a mellow and serene atmosphere like that of a mountain stream.

"When looking from some distance, viewers will be caught by the amount of detail in those drawings, all of which are arranged in an orderly and meticulous way," Zhu Heng says.

"If they come closer, they will find that grandpa drew with his fingers in a quite relaxed manner, a result of solid training in his early years and an accumulation of experience throughout the decades."

Born with the proverbial silver spoon, Zhu Danian was expected by his commercially successful father to one day inherit the family business. But he attended the Hangzhou Fine Arts School, now China Academy of Art in Hangzhou, Zhejiang province, and later the Central Academy of Fine Arts in Beijing, studying classical Chinese paintings, oil paintings and sculpture. In the 1930s he went to Tokyo fine arts school, now Tokyo University of the Arts, where he studied under several Japanese masters of ceramic art.

Such rich experience allowed him to bridge the past and present, and East and West in his work, whether he worked with paper or on ceramics and murals.

He traveled extensively throughout the country. The paintings on show reflect his love of nature, especially a passion for depicting the dense tropical forests, plants and birds in Xishuangbanna, Yunnan province, which he visited more than once.