Have you ever found, when playing a passage in music that required long periods of détaché bowing, that your bow arm got increasingly tired and your sound lost its resonance? If so, it can be useful to rethink the "plane" of the string at which you're playing.
In Chapter Two of Cello Practice, Cello Performance, I proposed a bowing technique that I called "Infinity Bowing." I wrote:
"When done correctly, infinity bowing is a much more elegant, less tiring method for changing the bow than a horizontal back-and-forth "sawing" method...Infinity bowing, by altering the elevation of the arm over bow changes, not only makes bow changes smoother but also helps create a more resonant tone." (p. 9)
In this chapter, I was talking more about long bow strokes than short ones. But my "infinity" method, where you imagine your bow hand's trajectory in the air as an infinity symbol (like a sideways 8) rather than as a series of back-and-forth straight lines, applies to any kind of bow stroke.
Let's take the example of Etude No. 6 from Popper's High School of Cello Playing. There are two things that make this etude hard. One is the intense chromaticism in the high register in the middle section. The other is the stroke, which needs to be a light, clear détaché.
It's very easy for your right hand to get tired and tense playing this piece, and for the sound to take on an unclear, "scuffling" quality. The way to preempt this is to make a "scooping" stroke with your bow, keeping the joints of your knuckles and wrists very loose, so that your bow can rebound energetically with less effort from you. Here's how to do it.
1. Place your bow on the string at approximately the balance point. Further towards the frog will make the stroke too heavy, and further towards the tip will make a lot of extra work for your arm.
2. Now, find the right "plane" for the down-bow and up-bow strokes. There are a lot of planes on which you can play on a string without bumping into an adjacent string, so for the down-bow stroke, play on the right plane of the string, and for the up-bow stroke, play on the left plane of the string. Here's what this looks like from the player's point of view. Click on the photo to scroll between the down-bow and up-bow stroke.
And here's what it looks like to the observer. Click on the photo to scroll between the down-bow and up-bow stroke.
Note that the bow should always stay parallel to the bridge during non-horizontal bowstrokes. Non-horizontal does not mean non-parallel. You're altering the side of the string you play on, not the angle of the bow vs. the bridge.