Whereas Delaunay's influence on younger artists such as Klee, Macke and Marc was that of a pioneer setting an example for those who follow, Kandinsky was already well-along on his own path to non-objective painting, and his relationship with Delaunay was more complex and reciprocal, and of critical importance in understanding the forces that propelled a handful of artists toward abstract painting before 1914.
A significant intermediary in this relationship was Elizabeth Epstein, a student of artist Eugen Kahler, about whose painting Kandinsky had written in Der Blaue Reiter almanac. Epstein was friendly with Delaunay's wife Sonia, who, like Kandinsky, was an expatriate Russian. Delaunay asked Epstein to translate Kandinsky's writings for him. Epstein had seen Kandinsky's paintings at the 1911 Salon des Indepéndants in Paris, and drew Delaunay's attention to them. Delaunay's essays, especially Sur la lumière, may have been influenced by Kandinsky's writings, such as Über das Geistige in der Kunst (Concerning the Spiritual in Art), published in Munich, 1912.
Although Kandinsky's and Delaunay's early, non-objective paintings are outwardly very different, there are several parallel tendencies in their evolution towards abstraction. The residual imagery observable in Delaunay's Eiffel Tower and Fenêtres series is comparable to Kandinsky's implicit references to horses, riders and romantic landscape motifs. Both artists in their writings discuss the important role of color in the creation of abstract painting. Both artists had a deep interest in mystical and occult texts. Virginia Spate has proposed that Delaunay's movement away from the grid format of the Fenêtres series to the adoption of circular or spherical shapes is a consequence of Delaunay's interest in the floating, rounded forms in Kandinsky's paintings, and notes that Delaunay did not begin his Formes circulaires series until after he had seen the Kandinsky paintings in the January-February, 1913 exhibition at Walden's Der Sturm gallery in Berlin.
After 1913 the paths of these artists began to diverge. Delaunay returned to the use of recognizable subject matter, while Kandinsky's work remained fundamentally abstract (even if he does incorporate earlier romantic imagery) after his return to Russia in late 1914, and became increasingly geometric in response to the work of the Constructivists and Suprematists. Here Kandinsky retains the floating, organic forms of his earlier abstraction, and at the same time, similar to other works of this period, utilizes the compositional device of a border, which emphasizes the flat, planar character of the composition, and the centralized focus of his forms.