Two of the most important themes in Chua Hu's paintings during the 70's were "Iron Bridge" and "Riverbank". Back in 1971, Taiwan's Hsiung Shih Art Monthly No. 8, the October issue translated and published significant Philippine art scholar Jesus T. Peralta's discourse, Chua Hu and his paintings. On Chua Hu's "Iron Bridge" paintings, he noted "Chua Hu used a much abstract way to handle natural forms; I believe if he continues adapting this approach, he could completely abandon or could at least minimize these composition elements."

And in this brilliant "Iron Bridge and Riverbank" from 1974 has proved Jesus T. Peralta's prediction right. Chua Hu was seemed to try water-inking western oil paints in this dual themed painting. He treated oil blue paints as Chinese black inks, let it naturally embroiders and flows on canvas, in the mean time he left plenty of "white spaces" to make contrast, to create dimensions in the picture; The brush strokes he applied also enhanced the kinetic energy, made the whole painting wonders beautifully between concrete and abstract.

In his early days when Chua Hu was interviewed by press he was being asked "What is your purpose to paint?" He replied "The reason why I took art as my career is because I want to use a brand new artistic form to carry forward traditional Chinese Ink Paintings." And this piece indeed realized his declaration. On forms, he made himself closer to western abstracts, on the essence, his more Chinese than ever. "Iron Bridge and Riverbank" could be the "milestone" throughout his artistic career.