By Paul Stein: For each strength that you may possess as a musician, you can count on at least two weaknesses. Before you think that sounds like negativity talking, consider that I didnt say ten weaknesses. (Much closer to the truth.) One common characteristic of a weakness is that its simply not even thought about, much less actually worked on. On the other hand, the good news is that certain skills may be strong because they come naturally to the player. The best advice is to constantly strive to improve, which will help mitigate the feeling that is common to many musicians, that we dont understand what were doing.
The students morale and confidence improve when all the technical parts are level with each other. If the bow arm is stronger, work on the left hand. However, most of the time the left hand is far more developed. The bow arm is, at best, merely an after-thought. More likely it is, for all intent and purposes, ignored.
Horse Before the Cart
It takes a very directed and determined musician to dig him or herself out of a technical hole. The development of the bow arm should proceed from a clear understanding of the concepts, followed by exercises. Usually its the other way around. Consider the bow that is virtually unable to stay in the general area between the bridge and fingerboard. To borrow a term from tennis, lets call it the sweet spot. (Is there a term we use for that area, other than sounding point?)
Teachers understand how difficult it is to address this issue, and its even more frustrating when the student is adept at far more difficult techniques. This is one of the examples of fuzzy logic when addressing musical development. If a student is good at conveying musical feeling without having to work at it, but slow when it comes to fixing something that doesnt come natural, the two opposite extremes need to come together.
The Hydraulic Drifter
Left to its own devices, the bow resists being where it needs to be. A simple explanation based on physics should start the discovery process. I use the term simple advisedly, since natural, common sense often flies in the face of bad habits mastered over a lifetime.
The bodys natural placement of the arm does not necessarily take into account the change of planes inhabited by each string. Place the bow on the A string at a customary 90 degree angle, then place it on the D string. If your body and mind havent been re-wired to a violinists specifications, the mind will still be on the A string, but not on the D. (Love it or hate it, the language of physics is clear but annoyingly pervasive.)
The solution starts with cleansing your palate in order to quit thinking about the A string. Be prepared for the difficulty of feeling the new plane of the D string, so that youre primed for the change. The body is more than happy to accommodate change when the mind is ready. Easier said than done. The mind will put up a huge, but not heroic, resistance before it changes its perception.
As you change from the A to the E string, allow your elbow to feel like its moving backwards, traveling further behind your body as you move towards the tip. With so much freedom of the arm, you would think that the bow tip would drift towards the fingerboard. What keeps that from happening is that the bow itself is led by its own compartment within the mind. By concentrating on the actual part of the bow thats touching the string at any given moment (known as the playing point), the bow will remain independent of the arm movements. These compartments keep techniques interdependent, which ensures a solid, flexible approach to playing.
Unless this natural movement happens, a very unfortunate side-effect takes place: the bow is at the mercy of a hydraulic movement forwards, towards the fingerboard. And with each string change, the chaotic drift brings the bow dangerously close to the edges of the violin.
Planes, Performers and Perception
The most important quality of a straight bow and natural, flowing arm is that the mind is on the bow and not on the arm. (Think about the intricate movements involved in simply picking up a salt shaker and turning it upside down. The arm, fingers and wrist react naturally.). Necessity dictates that our first bowing lessons instruct us on how to move the arm, not the bow. Of course, that type of lesson is practically unavoidable.
There is a common tendency in which the arm becomes fixed, and does not move to the new position that the changing planes of the string require. There is an exercise to ensure that the bow will start out at the correct angle on each string.
It depends on the student thinking only of the bow, and letting the arm follow naturally. The downbow and upbow movements should not be included at this time because of the complications that would happen immediately. Just think of this as an exercise to isolate how the mind perceives the change of planes of the strings.
The object of the exercise is to show that if the player visualizes the planes of the strings, the arm movements will unfold naturally, without a conscious, learned effort. Any bow hold will be suitable, because the various parts like the wrist and fingers will move correctly to accommodate the changing planes.

While staying in the same part of the bow without moving down or up, place the bow perpendicular to the string. (Dont look at the fingerboard or the bow, because the view will mislead you. Improve your ability to know where they are without looking.) Now move to a different string, making subtle but important changes in wrist angle and elbow placement. Notice that the bows position is the dominant thought; the hand, wrist and elbow just go along for the ride. Change to different strings, sometimes skipping one or two strings. Allow free passage of all the moving parts of the arm. The reason not to move the bow up or down is because every tiny movement alters how the arm accomodates the bow. Once you learn how passive this process is, the arm is ready for any movement of the bow to any position.Convince Yourself That Change Feels Good Considering that many of us started playing with the violin directly in front of our bodies, with the bow zig-zagging at 45 degrees, its a testament to the perseverance of our teachers and ourselves that we could transform such a limiting technique. With any change comes the nagging feeling that were doing something completely wrong and uncomfortable. Say what you will about an old bad habit, its still as comfortable as an old, worn slipper. So when you are making good changes, tell yourself and remind yourself that it feels natural. Fake it until you make it!