In Baroque times, people thought that B minor was the key of passivesuffering. Christian Friedrich Daniel Schubart (1739-1791) said that it was a key that was complaining gently and quietly, something that matches Bach's use of the key in the St. John's Passion. By Beethoven's time, B minor had changed in people's minds: Francesco Galeazzi wrote that B minor was not suitable for music in good taste, and Beethoven labelled a B minor melodic idea in one of his sketchbooks as a "black key". The chord was famously used as the first chord in Pink Floyd's 1979 hit "Comfortably Numb", commonly renowned to be a very emotional and melancholic song.[source?] The second movement of Rodrigo's Concierto de Aranjuez, one of the most famous compositions for the classical guitar, is in B minor.
It is a common key used in rock, folk, country and other guitarist-based styles because a guitar is naturally tuned so that all the open strings are notes in B minor.
↑Michael C. Tusa, "Beethoven's "C-Minor Mood": Some Thoughts on the Structural Implications of Key Choice" in Beethoven Forum 2, Christoph Reynolds, ed. Lincoln: University of Nebraska Press (1993): 2 - 3, n. 5