The fact that the slurs are featured in CJ only makes us think that they could have been added by Chopin, who might have had the opportunity to go over this copy. However, it is an assumption only that actually does not influence the evaluation of authenticity of these slurs in any way.
The slurs in CB must be an arbitrary addition of the writer, who provided the L.H. part with slurs in the entire piece.
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issues: Balakirev's revisions
notation: Slurs