  We explore the entropic uncertainty relation in the curved background outside
a Schwarzschild black hole, and find that Hawking radiation introduces a
nontrivial modification on the uncertainty bound for particular observer,
therefore it could be witnessed by proper uncertainty game experimentally. We
first investigate an uncertainty game between a free falling observer and his
static partner holding a quantum memory initially entangled with the quantum
system to be measured. Due to the information loss from Hawking decoherence, we
find an inevitable increase of the uncertainty on the outcome of measurements
in the view of static observer, which is dependent on the mass of the black
hole, the distance of observer from event horizon, and the mode frequency of
quantum memory. To illustrate the generality of this paradigm, we relate the
entropic uncertainty bound with other uncertainty probe, e.g., time-energy
uncertainty. In an alternative game between two static players, we show that
quantum information of qubit can be transferred to quantum memory through a
bath of fluctuating quantum fields outside the black hole. For a particular
choice of initial state, we show that the Hawking decoherence cannot counteract
entanglement generation after the dynamical evolution of system, which triggers
an effectively reduced uncertainty bound that violates the intrinsic limit
$-\log_2c$. Numerically estimation for a proper choice of initial state shows
that our result is comparable with possible real experiments. Finally, a
discussion on the black hole firewall paradox in the context of entropic
uncertainty relation is given.
