It is a surprising fact that until the twentieth century, the repertoire for two pianos was sadly inadequate. Before then it consisted of virtually twenty-two works—if we consider major two-piano composers—by Pasquini, Couperin, the Bach family, Clementi, Mozart, Schumann, Chopin, Brahms, and Rachmaninoff. Even the standard twentieth-century repertoire contains five times the number of works written during the previous three hundred years.

The growing interest among composers for two-piano works was linked to the increasing number of duo-pianists on the concert circuit. They established and maintained the standard repertoire and composed new works for two pianos. Let us consider three who have left their mark: Debussy, Stravinsky, and Bartók.

Debussy: a strong advocate

Debussy was a strong advocate of the piano duo. In 1880 and 1881 he played mainly with Nadezhda von Meck, a Russian, who introduced him to the entire Tchaikovsky corpus. Debussy’s colourist leanings made him favour piano duos. He eventually performed the French premiere of Wagner’s Rheingold with pianist Raoul Pugno.

While Rachmaninoff was completing his Suite No.2 in 1901, Debussy was finishing Lindaraja, his first original composition for two pianos. This was a dry run for his masterpiece, En blanc et noir, which Debussy wrote during the summer of 1915. The three-movement suite with its poetry as frontispieces may evoke program music, but it certainly isn’t as pictorial as the Rachmaninoff composition. Debussy’s habit of attaching fake labels (or false clues) to compositions such as the Preludes was mainly intended to evoke a mysterious element.

Stravinsky

Proteus was obviously the god of twentieth-century artists and Stravinsky his most outstanding prophet. In a letter to Robert Craft, his secretary, he said he had composed both his Concerto per due piano-forte soli and the Sonata for Two Pianos “for the love of pure art.” He wrote the concerto’s first movement in 1931. Later, although Stravinsky was busy performing and conducting throughout Europe, he found time to focus on his masterpiece, Persephone. He completed the concerto’s three other movements in Paris in 1934-35 and premiered the work with his son Soulima at the Salle Gaveau on November 21, 1935.

Prior to the performance Stravinsky lectured on the work, stating that the “two pianos assume a concertante role in relation to one another,” so that this “concertante contest, by its very nature, requires a contrapuntal style.” Stravinsky’s genius here resides in the abundance and variety of his rhythms, which offer a multiplicity of expression. Even the unrelenting accompaniment of staccato sixteenth-notes in the first movement and the ostinato of the third movement (fourth variation) suggest progression, since they are combined with other rhythmic elements. As for harmony, Stravinsky’s relatively neoclassical stability soon gives way to a pandiatonic idiom sometimes bordering on atonalism, as in the variations. The originality of the Quattro variazioni lies in the fact that they are not so much variations on a theme as on compositional features (ornamentation and figuration in the first, glissando and octave exercises in the second, scherzando and velocity in the third, and chord technique in the fourth).

This uncompromising concerto demonstrates Stravinsky’s mature art, based on the piano as a percussive instrument. It can be daunting to listen to and a tour de force to perform. The piece’s drive only lets up in the Notturno, which the author described as a “cassation.” By comparison, Stravinsky’s three-movement Sonata for Two Pianos (1943-44) sounds more accessible and requires less virtuosity. Written during his American period, it reveals a bald style marked by his neoclassic tendency, with compositional features akin to Bach. This sonata is a wonderful example of modern counterpoint and pandiatonics, a method already encountered in his concerto (see the figure in the fourth variation). Taken as a whole, however, the sonata is far less savage than the concerto and reflects Stravinsky’s American period.

Bartók

Béla Bartók was still in Hungary when he wrote his Sonata for Two Pianos and Percussion in 1937. That same year his compositions were banned on German and Italian radio stations, since their Nazi and fascist managers had labelled them Entartete Musik (degenerate music). The man who composed The Miraculous Mandarin, The Cantata Profana, and Music for Strings, Percussion, and Celesta (1936) was nonetheless suspect. Apart from his communist inclinations during Belakun’s ephemeral presidency, Bartók was more interested in spending his time in the fields with Romanian and Hungarian farmers than plotting with big-city politicians.

Conscientiously or not, Bartók was reacting against the sinister developments in European civilization. He studied rural roots as a better model for art and the future. Bartók was strongly individualistic and had his wild side; in his music he echoed a world of instincts with a touch of neo-paganism. All these elements figure In his Sonata for Two Pianos and Percussion, one of his quintessential pieces. “At the beginning was the rhythm”: Von Bülow’s adage fits Bartók perfectly. He can generate all the energy he needs with rhythm. He has very little need for melody to give the music form. Consider his trivial, not to say tribal, theme in the first movement, right after the introduction, in which we find three quarter-beats on the same note followed by three sixteenth-notes, the middle one a third lower. Later this tonal cell is partially lost in a juxtaposition of blocs that include diatonic scales and bird-like songs (leaping sixths) alternating between the two pianos and marginally with the xylophone.

The sonata’s short recapitulation of the exposition is interesting not only for its rhythmic, driving energy. Compared to the fugue, this monumental movement has far greater importance, only challenged by the impressive progression of the introduction. The brilliant diatonic scale of the third movement is also driven by rhythms and forms related to counterpoint.

Bartók was obsessed by precision. He had a very clear idea of the percussive sound effects he wanted. Eleven years earlier, he had already noted on the score of his first piano concerto how he wanted the percussion to be performed. For his two-piano works he even told his publisher to indicate the position of the pianos as well as each percussion group.

After the sonata’s American premiere Bartók added an orchestral version. He played what became his concerto for two pianos for the first time in January 1943 with the New York Philharmonic, directed by Fritz Reiner. The sonata was performed with his pupil, duo-pianist, and wife, Ditta Pásztory.