Bow hold

Violin, viola, and cello use variants of a hold in which the thumb bends outward against the frog and the fingers drape over the stick at slight angles. The double bass has two competing traditions: the French bow is held overhand much like a cello bow, and the German or Butler bow is held underhand, more like a saw handle.

Whatever the school, the shared requirement is flexibility. A locked thumb or a straight index finger transmits arm tension straight into the string and produces a scratchy, uncontrolled tone at any dynamic above mezzo-forte. This is the one element of string technique that genuinely benefits from a teacher physically checking it, because the difference between a functional and a damaging hold is not always visible to the player.