On August 18, 1939, after he had just completed his Divertimento for string orchestra, Bartók wrote to his son Béla from Saanen, Switzerland, where he was on a composing vacation. “Now I have another commission to fulfill, this time a string quartet for Z. Székely (i.e. for the ‘New Hungarian Quartet’).” In the same letter he expressed his concern over the political situation. He had noted that people in Switzerland were feverishly preparing for the outbreak of war: papers wrote about military matters, and barricades were being built in the passes to stop tanks. “I do not like you going to Romania – in such uncertain times it is unwise to go anywhere so unsafe. I am also worried about whether I shall be able to get home from here if this or that happens.” However, Bartók added, “Fortunately I can put this worry out of my mind if I have to—it does not disturb my work.”

Bartók evidently got into the business of composing the quartet quite well (the Divertimento had been completed in 15 days), but he only had 6–7 days of peace for his work. In the last week of August, after hearing of the non-aggression pact signed by Germany and the Soviet Union (on August 23rd), he packed his bags and rushed to Budapest. He continued his work at home, however, and on September 29th he was able to notify Géza Frid in Amsterdam: “The three first movements of the Sixth Quartet are ready (one – the fourth movement – is still lacking).” Bartók completed the missing fourth movement in November. But something in it bothered him. When he sent the manuscript of the work to his publisher in London on February 25, 1940, he wrote, “It must not be printed without separate notice; I might change the fourth movement later.” He did not change it, however. The fourth movement remained and was the last quartet movement Bartók ever wrote.

We have Bartók’s drafts for the quartet. They show that the composer planned a rapid dance movement, whose themes were to be openly folkloristic and which would progress like a perpetuum mobile, as the finale. This plan evidently preoccupied him as late as February, when he did not give his publisher permission to print the work. Why did a finale built upon a ritornello theme and motives from the first movement, which rounds out the work nicely, not satisfy him?

I presume that the solution to this mystery can be found in the two middle movements, which Bartók gave the names Marcia and Burletta. The Marcia and the Burletta are character pieces, linked to the rhapsody tradition. Like Liszt’s Hungarian Rhapsodies, they have elements of the rustic verbunkos style, which was very popular in Hungary during the 19th century. The verbunkos is a recruiter’s dance. It usually comprises a slow dance section (lassù) followed by a rapid section (friss). Bartók had used this structure previously, e.g. in his Contrasts for violin, clarinet, and piano (1938) and in both his rhapsodies for violin and piano or orchestra (1928).

Marcia corresponds in character to the lassù dance. Its main theme, in a dotted rhythm, with a highly aggressive tone, has the same kind of motive as the main theme in the ‘Verbunkos’, first movement of the Contrasts, and the Rumanian melody, which is the main theme in the last section of the First Rhapsody for violin. Bartók described this Rumanian melody as one of the 2/4 dance melodies to which a strict dotted rhythm “gives a march-like, ‘heroic’ character.” The dotted rhythm in the main theme of the Marcia is a kind of semantic element for which the whole movement was given its name. But Bartók’s march is not an idealized march of the kind which one occasionally meets in Mozart’s piano concertos (e.g. K. 503). It is brutal, grotesque and ironic – and not triumphant. It is thus appropriate for an intensive, pain-filled plaint to rise in the violins under this stubborn dotted rhythm, taking on the role of the second theme in the main section. There are models for this theme, too, in Bartók’s earlier works. The closest model can be found in the slow movement of the other work written during that oppressive August in Saanen, the Divertimento.

The Burletta has features characteristic of the rapid friss dance, even though the movement’s tempo is only Moderato. One such feature is the theme, surrounded by expansive interval jumps, with which the movement begins and which, together with the “out of tune” glissando in quarter tones, mostly accounts for its burlesque character. Since the Burletta is, however, a slow movement, it does not have the nature of a finale, which is part of the friss dance. Did Bartók feel that, since the Sixth String Quartet includes all the other central elements of the rhapsody, it would remain incomplete without a rapid dance as its finale? This would explain his doubts. We will probably never know whether the final solution to the problem of the finale was influenced by purely artistic considerations or by the outbreak of the war, Bartók’s emigration to the United States or other external conditions.

The Marcia and Burletta form the most important parts of the Sixth Quartet as far as content goes. A second force field, which extends its effect over the whole work, is the Mesto theme played by the solo viola, beginning the work and repeated at the beginning of each movement, taking on the significance of a ritornello. This theme, which Bartók’s drafts show was polished thoroughly, becomes so important as the work progresses, that it could after all have made the idea of writing a folkloristic dance finale completely impossible.