  The Kitaev spin liquid, a ground state of the bond-dependent Kitaev model in
a honeycomb lattice has been a centre of attraction, since a microscopic theory
to realize such an interaction in solid-state materials was discovered. A
challenge in real materials though is the presence of the Heisenberg and
another bond-dependent Gamma interactions detrimental to the Kitaev spin
liquid, and there have been many debates on their relative strengths. Here we
offer a strategy to extract the Kitaev interaction out of a full microscopic
model by utilizing the symmetries of the Hamiltonian. Two tilted magnetic field
directions related by a two-fold rotational symmetry generate distinct spin
excitations originating from a specific combination of the Kitaev and Gamma
interactions. Together with the in- and out-of-plane magnetic anisotropy, one
can determine the Kitaev and Gamma interactions separately. Dynamic spin
structure factors are presented to motivate future experiments. The proposed
setups will advance the search for Kitaev materials.
