  One of the XRISM mission goals is to measure the gas dynamics of galaxy
clusters with Resolve spectroscopy. To archive these, we propose an observation
of the X-ray bright galaxy cluster Abell 2256 at z=0.06. This hosts 2nd
brightest diffuse radio relic. Suzaku revealed a gas bulk motion at 1500 km/s,
for the first time i\ n a cluster. This X-ray gas velocity is consistent with
those measured in galaxy velocities, indicating that gas and galaxies are
moving together. These and other observations make this system the most
suitable for the XRISM spectral mapping of gas bulk and tur\ bulent motions and
related physics. We propose two pointings to cover the central ~400kpc region.
