Left hand
Designation of the lower piano part.
What it means
In piano writing, “left hand” designates the lower of the two staves and thus, as a rule, the deeper part of the texture. The assignment is practical, not binding: what stands in the lower staff is usually played with the left hand, but the notation can explicitly demand something different. What decides is the sound, not the convenience of the division.
In the notation
The lower staff usually carries the bass clef but switches to the treble clef at a high register, without the hand thereby changing. Common indications are the Italian abbreviations for the hands, as well as arrows or brackets showing that one hand reaches into the other's staff. Notes played by the right hand in the lower staff appear there with a corresponding note; conversely, a low note of the left hand occasionally stands in the upper staff, when that saves ledger lines. In polyphonic writing, stem direction shows which voices belong together — not membership in a staff.
Musical use
In classical piano writing, the left hand is usually assigned bass and accompanying figures: broken triads as in the Alberti bass, chordal support, octave doublings. In this way it carries the harmony and the rhythmic framework. In polyphonic music the picture shifts completely, for there it leads voices of equal standing, often several at once. In Romantic literature, too, it often takes over the melody in the middle register, while the right hand plays figuration around it.
In piano notation the left hand is marked l.H., m.s. for mano sinistra, or m.g. for main gauche. Normally it is notated in the lower staff, but crossings and reassignments between the hands are frequent, especially in Romantic piano music. There is also a repertoire written specifically for the left hand alone.
Performance practice
Practise the left hand regularly alone and at sight — it easily becomes an afterthought in two-handed playing, and note-reading in the bass clef then falls behind. Watch the balance: the bass carries but should not cover the melody; accompanying figures sound best light and even. At places where the hands cross or reach into the same staff, write in the assignment before you increase the tempo.