The outer triangle or ‘frame’ of the bow hand, consisting of 1st finger, 4th finger and thumb, is pivotal to controlling the bow while in the air. If the thumb locks, often the 1st and 4th fingers also lock. Most importantly if the 1st finger grips the bow too hard then none of the joints in the hand are flexible enough to allow a gentle landing of the bow onto the string. Imagine jumping on the spot with locked knee joints; you would not be able to control the landing or the next jump very well.
We almost never perform without the first finger on the bow as the bow feels less stable (especially when it is in the air). It is however an excellent exercise to play without the first finger when practising A slow to moderate speed bouncing stroke., down bow retakes or basically any stroke in the lower half of the bow.
The reasons for this are:
– practising without the first finger makes sure the 4th finger is in a useful position to actively support the bow while in the air. If we lift the bow into the air and take the first finger off, we ought to be able to maintain the bow in the air. If the bow instantly falls, then the other fingers are not doing their job!
– when practising spiccato the joints in the hand (base knuckles) need to be flexible. Taking away the first finger concentrates our attention on otherwise hidden issues.
-We learn we can make a strong resonant sound in the lower half without any added The degree of contact between bowhair and string. from the first finger, as the weight of the bow is sufficient when it is allowed to sink into the string.