At the outbreak of WWI, Georges Vantongerloo left Belgium for The Hague. He soon made connections with the Dutch avant-garde and kept in touch with like-minded artists, above all Theo Van Doesburg. In November 1918 he signed the manifesto of De Stijl alongside Piet Mondriaan, Van Doesburg and others, the only Belgian artist to do so. His first abstract works were sculptures. Parallel to this, in painting he sought out the spatial potential of colour. Unlike most of the artists of De Stijl, who used only the primary colours red, blue and yellow Vantongerloo introduced secondary colours into his painted works. The painting Study no. III is one of the earliest examples. It illustrates his colour theory, in which he establishes seven principal colours: red, orange, yellow, green, blue, indigo and violet. In addition, he distinguished five transitional colours, being red-orange, yellow-orange, blue-green, indigo-blue and indigo-violet. It is no coincidence that this amounts to twelve colours, whereby Vantongerloo linked his palette to twelve-tone music. This painting has the nature of an experiment in which Vantongerloo puts his colour theory into practice.