Planning bow division is another way of practicing tone production since it involves all of the same variables of speed, pressure and point of contact.
It is good to focus on each variable in turn.
This still picture shows Fintan at the heel; in the next item bowing in the lower half is planned during slow practice of Bach.
The repertoire of J.S.Bach presents many bow division challenges. These are often resolved by using more bow on the up-bows to regain the ground we lose on the down-bow slurs (travel bowing).
Remember that our modern bow (the Tourte bow) is different to the bow that Bach would have used. The Tourte bow can project a stronger sound but is less agile when it comes to playing passages like these.
Practise your bow division at half tempo and use the mirror.
This is Bars 24 to 32 from the 1st movement of Bachs Concerto in A Minor.
Scores - Bow Planning in Bach A Minor - violin & viola
Resources - Repertoire