Janus, one of the lesser known Roman deities, was the god of beginnings and endings, of transitions, duality and of time. More notably, Janus presided over the beginning and ending of conflict. He was usually depicted as having two faces, looking to the future and to the past.

The piece begins with five pitches which together make up two unrelated triads, Bb minor and Gb minor. The triads share one common pitch – Db. The five pitches are the only ones used as the piece opens with percussion and strings followed by the woodwind. The calm opening then switches abruptly to a more menacing, violent section in the brass, using the same five pitches.

As the piece progresses, other pitches enter the fray, sometimes individually, sometimes adding all remaining seven pitches to complete the entire chromatic scale. The calm opening reappears, this time on the brass before the violent section returns. The closing passage recalls the peaceful opening on strings and woodwind before the two triads make a final muted appearance, briefly colliding and then resolving.