The reputation of Leonardo da Vinci is like an inverted pyramid — a massive, impressive structure that can draw a vast audience, but stands on an extremely narrow base. Although regarded as one of the "Big Three" artists of the Renaissance — along with Michelangelo and Raphael — the paintings on which this reputation is based are remarkably few.
These simple facts — big reputation plus extremely small body of work — mean that Leonardo exhibitions tend to be disappointing. They can't present more than one or two of his finished paintings, and are therefore forced to eke out the rest of the show with works by connected artists or pages from his notebooks, which are more plentiful.
Naturally this is what the Leonardo da Vinci exhibition now at the Tokyo Metropolitan Museum of Art does. Even within such unavoidable constraints, it is still possible for a Leonardo show to succeed, but it depends on two main factors: First, the quality of whichever Leonardo painting or paintings that the organizers can get their hands on; and, second, the quality of the works by the associated artists.