Painter Chua Hu's two most important themes in his series of works in the 1970s are "iron bridge" and "river bank." The 8th issue of Taiwan's Hsiung Shih Art Monthly published in October 1971 carried a translated article "Chua Hu and His Paintings" written by the Philippines' highly respected art historian Jesus T. Peralta. With regard to the "iron bridge" works, Peralta mentioned that Chua "becomes more abstract while dealing with natural forms than before. It is believed that he will perhaps completely give up or at least reduce the constructional elements in his future works."

Looking at Chua's brilliant works of Iron Bridge and Riverbank which were created in 1974, one will realize that Peralta's prediction is quite true. In the work combing the theme of "iron bridge" with that of "river bank," the painter seems to give a Western oil painting the look of a Chinese water-ink painting. He treats blue with black ink and lets oil paints naturally play up and run through a canvas on their own courses. Meantime, he also uses "white space" to create a contrast between darkness and brightness in order to give a sense of space. With strokes, it enhances the painting with a sense of "force and energy". Such an arrangement gives the whole painting an indescribably dream-like and indistinct beauty.

Chua Hu's was once asked about the "purpose of painting" during an interview in his younger days. He answered: "The purpose for which I am engaged in art work is to make use of new art forms to add glory to the great Chinese landscape paintings." The accomplishment of the Iron Bridge and Riverbank indeed offers a proof of his own manifesto. In the pictorial form, he allows himself to be closer to Western abstraction whereas his pictorial contents are more Chinese. Iron Bridge and Riverbank can be said to constitute a very crucial "milestone" in his art career.