I have been learning the Unaccompanied Suites for Violincello by Bach with an edition by Maurice Gendron. Gendron's indication of bowing seemed to me as quite technical and complicated at first. For example, the 1st bar of the prelude in the 1st suite was often indicated to play in one down bow. Gendron's edition tells us to play only first 3 of 1/16 notes in a slur. The rests in the bar are played in one bow for each note. Here is the manuscript of this piece. The former has long been familiar to my ears.
Recently, I have had a chance to look the manuscript of this work by Bach himself. I was surprised to know Bach had indicated detailed bowing in each piece. Gendron's edition has adopted the original indication by Bach. Bowing is essential for expression with any string instrument. Lately, before investigating Bach's manuscript thoroughly, I have become feeling this apparently complicated bowing for this work by Gendron had been musically very expressive and excellent. I was very happy to know it might had been because I listened to what Bach himself thought in his composition.
And, imagining what Bach thought and felt while composing a particular phrase, I go on practising it.
PS: I have misunderstood as if the manuscript had been written by Bach himself. It was by his wife, Anna Magdalena. It still, I believe, reflect Bach's idea on bowing. Some cellists insist that this manuscript is not perfect but has some evident mistakes. But, when I practise the prelude of the 3rd suite, I feel the bowing by Anna Magdalena through Gendron expresses something very excellent. In my view, the bowing technique Anna Magalena employs serves to materialize Bach's intention.