Technique: achieving balance between the chin and left thumb

The function of the left-hand thumb is very important in string playing, but to many people it is rather mysterious. Often when we start to play a violin or viola, the neck naturally falls into the comfortable nook between our thumb and first finger. This makes it impossible to manoeuvre with the left hand, so the teacher says, ‘Your thumb needs to be lower’, and as a result many players hold the thumb low against the side of the neck for the rest of their lives. That can cause problems on the viola, which is larger and heavier than the violin: an incorrectly placed left thumb does not offer enough vertical support and forces all the weight of the instrument on to the shoulder and chin, which can lead to excess tension and pain.When we are playing between first and third positions on the viola, it is in fact best to position the thumb relatively high, for maximum contact. This takes some of the pressure away from the chin and helps the arm to support the instrument, balancing the workload between the jaw and the thumb. Of course, if the thumb is doing too much work to support the instrument, it is difficult to shift freely, play in tune or control your vibrato. If the thumb is not working enough, the chin and shoulder will have to compensate, passing tension down into the arm and giving the same result.