# Thumb position

Source: https://arcosounds.com/glossary/thumb-position

**Thumb position is a cello and double bass technique in which the left thumb leaves the back of the neck and presses down on the string itself, acting as a movable nut.**

High on the fingerboard the neck of a cello or bass gets in the way of the conventional hand shape, and the distances between notes shrink. Bringing the thumb onto the string solves both problems: it stops a note of its own, usually alongside the octave harmonic, and gives the hand a fixed anchor to measure from.

The thumb is laid across the string sideways, using the fleshy side rather than the tip, and it very often stops two strings at once to enable octaves and fifths. It is demanding, the thumb has no callus and no experience of stopping a string, and it is normally a third or fourth year technique.

Violinists and violists never need it: their fingerboards are short enough that the standard hand shape reaches the top of the range.

Canonical source: https://arcosounds.com/glossary/thumb-position