Yasunji Kiyose's early works were rooted in German Romanticism, but he gradually began to question this style. As he embarked on self-study in composition, he became increasingly influenced by Impressionism. Furthermore, he intentionally employed Japanese pentatonic scales in his compositions, creating music that was familiar to the Japanese sensibility and did not rely on virtuosity. Four Preludes, written when Japan was still in the desolation and confusion of the post-war period, shows a departure from his pre-war style. The number of notes used increased, and the pieces became "rich in thematic variation and vitality." As the composer himself stated, "These preludes were written to express the helpless feeling of the post-war era; one could say they emerged from this sentiment." The collection begins with the first prelude, which flows beautifully yet aimlessly throughout, leading to the second and third preludes, which, influenced by this suggestion, "contain a mysterious tranquility and a hidden lamentation." The concluding fourth prelude begins with "the impatience stemming from the various instabilities of the post-war period," proceeds through a lamentoso middle section expressing "mourning for the war dead" and "sympathy for those displaced by fire," and then moves towards a finale that "returns to anxiety and impatience but concludes powerfully, anticipating reconstruction."