The artist Jorge Oteiza (Orio, Spain, 1908-2003) is considered one of the main sculptors of the 20th century. Jorge Oteiza won the International Sculpture Prize at the IV São Paulo Biennial, held in 1957, which elevated him internationally. Oteiza's conceptual evolution as a sculptor moves him towards a special relationship with the unoccupied space, the void, seeking a metaphysics of space through absence or negativity, where light also plays a prominent role, being incorporated into the sculptural process. These ideas are concretized in the negative relief mural that he calls Direct Relief / Homage to Bach (1956). This exceptional work from the limited production of his mural works provides an interesting field of study that helps complete the understanding of his thinking and the keys to his aesthetics. Nevertheless, this work is not only close to a plastic-spatial dimension. The work also conveys the special relationship of the Oriotarra sculptor with music in general and Baroque in particular and his concern for serialist avant-garde music and its possibility of plastic representation. The present article tries to make an approach to the interpretation of this work, studying in an analytical and synthetic way the artistic, musical and plastic thought of the artist.