Rubato must emerge spontaneously from the music, it can’t be calculated but must be totally free. It’s not even something you can teach: each performer must feel it on the basis of his or her own sensitivity. There’s no magic formula: to assume otherwise would be ridiculous.¹
There is a concept in music called rubato. It is essentially rhythmic improvisation—an unrestricted tempo indication that breaks passages free of their strict metronomic pulse and open to a more visceral emotional interpretation.
In a piece of music, the composer will mark rubato in the same way he or she will mark allegro, presto, or adagietto. There is actually a standardized vocabulary that composers use to best describe the approximate speed a piece should be played at. I do stress “approximate.” For instance, andante is literally translated as “walking” and indicates what is essentially a walking pace. But if one is a particularly fast walker then this direction can be grossly misinterpreted…
Rubato, when used tastefully and in accordance with a music’s ebb and flow, can bring heat and vigor to the composition. It is also the mark of a generous composer. When one dedicates months, often years, to create and refine a work down to the finest of grace notes and layered rhythms and chords, it is only the most confident among us who can let go of the reigns, if only for a few measures, and let the musician off the leash. Depending on the mood of the player, the age of the instrument, and the happiness of the audience, the rubato section can take on very different feelings from performance to performance. (For more on the power of an audience to affect reality, look no further than The Observer Effect in physics…)
To me, rubato is the act of letting go, both for the composer and the musician. The composer must let go of her work and leave it in the hands of the performer, and the performer must let go of his innate tendency to read music visually instead of emotionally.
Rubato, then, is simply the art of living. It is one’s ability and willingness to use plans and goals (and sheet music) to guide the journey rather than govern it.
(Rubato is also featured in pop music. The most obvious example can be heard in Billy Joel’s “And So It Goes.”)