The works of Zao in the 1960s and early 1970s often feature a subdued primary tone like black and brown and a robust, pushy brushstroke that power the dynamics of the frame. After mid-1970s the artist entered another creative stage. Alongside his matured oil painting skill, the colours Zao deployed become more vibrant and the emphasis on reconstructing space and light is even more apparent. His works, now getting closer to landscape, come to be the resting places of natural elements - water and fire, heaven and earth - and with a peaceful atmosphere. This is a period when Zao reverted to the artistic principles of Chinese ink painting and, at the same time, integrated it with Western oils. Pigments are handled in the ink-wash way: more turpentine is blended into the pigments, rendering the canvas in washes and splashes of colours. The brushwork is more sweeping and unbounded. All these are exemplified in 15-2-73 (Lot 1074), rightly considered to be representational to the works of Zao in this new creative stage. The sense of dimension is more agile and lively, and the colours seem even more suggestive of the faint wreathing mist. Following the vision of the artist, such vivid hues as olive green, ivory, greyish purple, sepia and greyish white are adeptly combined to form the variety of transmuting paints, either viscous or runny, hefty or floating. A consistent effort in interpreting oils is conspicuous; the artist strides across the limitations of oil pigments, which, eventually, are tamed and become the artist's followers - to follow his imagination, to recline on the liberal space the artist wants them to lay. 15-2-73 is a formalistic realm in a perfectly abstract form. The natural world therein, with all the rhythm of life, brings about illusions loaded with a profusion of aesthetic associations, by which means a transforming nature is accentuated. This is what may be called an Oriental painting of abstract form. By orientalizing the concept of "abstract" painting, Zao Wou-ki unifies the spirit of Chinese and Western art.
Zao moved on, in the 1980s and afterwards, to even more startling developments, which are presented in dramatic fashion in 18-3-83 (Lot 1072). The emphasis in these two works has shifted away from line and toward the free, unrestrained application of brilliant colours, frequently in shades of red, blue, yellow, and purple. Dappled with beautiful, multicoloured hues, the impression in these works is a feeling that colour itself is creating fantastic visual effects as they vibrate, spread, and evolve into new shades and tones that roll in grand waves across the canvas. Zao's washes of colour spread more freely than ever and project a grand sense of scale. Brushwork moves both horizontally and vertically, even seemingly into or out of the canvas, for textures that are three-dimensional in their effects, like rugged, craggy landscapes, yet the colours still retain a lightness and fluidity of their own. The artist finds spatial relationships here in the way different colours relate to each other. He devoted much thought and attention to this aspect of the relationships between colours, pointing out when he was lecturing in Hangzhou in 1985 that both his lines and his colours are "deep in some places, light in others, sometimes hot and sometimes cool, and always related to what is before and behind them." The interdependency of line and colour generates structure and visual context, and it is these pure artistic elements that produce aesthetic pleasure in Zao's work, informing the spaces he creates with a truly individual sense of style.
Compositionally, these two works show Zao's continuous effort to divide the canvas into horizontal segments, with the richest variations in colour occurring in the central portion due, where the sense of movement within space and energetic transformation is also strongest. Pure monochromatic tones appear in the upper and lower parts of the canvas, merging into large, continuous clusters of hues and shades where the roiling energies of the earth seem to burst into the open, beyond gravity, and float with light and graceful elegance. The work still preserves the Chinese aesthetic realms of "emptiness", "essence" and "purity". 18-3-83 seems to have construed up an idyllic imagery: a harsh winter passed, spring melts the ices on the frozen lake, reflecting the freshly grown wild grass on the bank. The twilight after sunset renders the scene in tender yellow and purple, in all respects romantic and affectionate. It is this light-hearted, graceful ambience that evokes every kind of muses from the audience.