  Nonlocal quantum correlation is at the heart of bizarre nature of quantum
physics. While there are various classes of nonlocal quantum correlation,
steerability of a quantum state by local measurements provides unique
operational features. Here, we theoretically and experimentally investigate the
hidden quantum steerability. In particular, we find that there are initially
unsteerable states which can reveal the steerability by using local filters on
individual quantum systems. It is remarkable that a certain set of local
filters are more effective on revealing steerability than Bell nonlocality
whereas there exists another set of filters that is more effective on revealing
Bell nonlocality than steerability. Finally, we present a counter-intuitive
result that mixed states originating from non-maximally pure entangled states
can have hidden steerability while the mixed state from a maximally pure
entangled state fails to show steerability.
