Abstract
In the J-PARC project, we are proposing two powder diffractometers. This article describes these powder diffractometers: a versatile diffractometer with resolution of Δd/d ≈ 0.1% for materials science and a high- resolution diffractometer with Δd/d ≈ 0.03% for precise analysis. Each of them looks at the other side of an off- centered decoupled hydrogen poisoned moderator. Another type of high intensity powder diffractometer is also proposed separately as a total scattering instrument.