Jonathan Hay, Ailsa Mellon Bruce Professor of Fine Arts at New York University, wrote an article for the catalog for an exhibition of works by Zao Wou-ki that was held in New York in 2003, in which he commented on the change in Zao's oil painting style in his later work: "In the course of 1979 Zao abandoned his older approach altogether and devoted himself entirely to the new stylistic direction that he had traced out for himself in a few key paintings of the 1970s. Out of this shift came a decade of work that attains a state of grace: a quality of gesture that is stripped of all hurriedness and creates a more powerful "bone-structure" (to use a term from Chinese calligraphy and painting), a luminosity extending from infinite softness to enveloping darkness, a topography of form that opens itself to stillness and silence." Jonathan Hay, 'Recent Works by Zao Wou-ki', 2003

Zao Wou-ki's paintings from the 1980s and 1990s embody a high degree of spirituality. The technique is effortless and mature. The intense, almost manic lines of some of Zao's earlier work are no longer to be seen; instead, there is spatial arrangement of great depth and meaning, with lighter, brighter and more lustrous color tones. The overall effect is intensely emotive and expressive – an exploration of the soul's wanderings in the cosmos. The stronger color tones that appear here and there in the paintings seem like a memory of the artist's youth. 15.7.93, painted in 1993, is one of Zao Wou-ki's finest recent works. A painting full of refined, elegant colors, it is not large in size, and yet offers unlimited scope for the imagination. Despite Zao's advancing years, his paintings seem as young and fresh as ever. Zao has succeeded in retaining the passionate enthusiasm of his youth. As he himself puts it, art "has no clear-cut ending." Zao feels impelled to continue painting; one cannot but admire his spirit and his commitment to his art.