Scriabin: Piano Sonata No. 9 ("Black Mass"), Op. 68

Although the single-movement sonata's nickname, Black Mass, was not invented by Scriabin (unlike the nickname White Mass given to his Seventh Sonata), he approved of it.

Like Scriabin's other late works, the piece is highly chromatic and atonal. The Black Mass Sonata is particularly dissonant because many of its themes are based around an interval of a minor ninth, one of the most unstable sounds. Its marking 'legendaire' exactly captures the sense of distant mysterious wailing which grows in force and menace. 

Like Scriabin's other sonatas, it is both technically and musically highly demanding for the pianist, sometimes extending to three staves as opposed to the standard two used in piano music.