Borscht and tears. It’s always fascinating — and enigmatic — to hear what a pianist will do with Schubert. The scores have few markings to lead the interpretation, and Schubert’s balancing act between simplicity and subsumed emotions is precarious. For a long time he wasn’t given the benefit of the doubt when it came to the basic issue of whether he knew how to write for the instrument. His sonatas, early and late, are marked by repetitiveness, peculiar key changes and abrupt mood swings that can seem eccentric, unless you accept that a genius knows what he’s doing even if we sometimes don’t. Beethoven tests a pianist’s moral character; Schubert tests a pianist’s ability to solve riddles.