The purpose of this study is to identify and elucidate the unique aspects of Isang Yun's compositional style through in-depth examination of his piano chamber works: Gasa for Violin and Piano, Garak for Flute and Piano, Nore for Cello and Piano and Riul for Clarinet and Piano. Isang Yun (1917-1995), a Korean-born composer, is renowned for having established a compositional language which expresses Eastern thought in music crafted from Western musical elements. He was a pioneer and leader who created new compositional techniques in his efforts to combine Western styles with Korean musical traditions. He achieved international acclaim for his highly developed compositional techniques such as Haupttontechnik (Main-tone Technique) and Hauptklangtechnik (Sound-complex Technique), which modernized and westernized ancient Korean performance practices and native Korean music traditions. Four chamber works for piano by Isang Yun are used to trace the development of his use of twelve-tone technique and Haupttontechnik and to identify the connection between his spiritual philosophies and his music. This essay provides these insights to give the reader a more complete understanding of the life and music of Isang Yun.