Abstract We have proposed a Versatile Inelastic Neutron Spectrometer (VINS) for the spallation neutron source at the Materials and Life Science Facility (MLF), Japan Proton Accelerator Research Complex (J-PARC). VINS is a direct-geometry Fermi chopper spectrometer designed to provide considerably high neutron flux with moderate energy and Q resolutions. VINS is characterized by its wide energy and Q range (0.5<Δ E<1000 meV and Q< 40 Å −1 at Δ E=1000 meV), enabled by an array of detectors covering large solid angle [−30°<2 θ<130° horizontally and −30°< φ<30° vertically (2.8 Sr)]. Monte Carlo ray-tracing simulation estimates the sample position neutron flux as high as roughly 1×10 6 neutrons cm −2 s −1 for the Δ E/ E i∼5% mode at E i=10 meV. With these wide E– Q coverage and high neutron flux, VINS will be one of the most efficient and versatile inelastic spectrometers at J-PARC. Target science ranges from conventional solid-state physics, such as highly correlated electron systems, frustrated magnets and relaxors, to rather interdisciplinary areas, exemplified by glasses, quasicrystals, polymers and liquids. A particular focus is placed on extreme sample environments; high magnetic-field and high-pressure environments are planned.