Review of X-ray dark-field imaging under development is presented. Its goal is its application to clini- cal diagnosis of organs that have been invisible by the ordinary techniques. In order to clinically visualize tissues in detail one needs high contrast and high spatial resolution say ~50 μm. This X-ray optics comprises a Bragg asymmet- ric monochro-collimator and a Bragg case or a Laue case filter with capability of analyzing angle in a parallel posi- tion. Their diffraction index is 4,4,0 and the X-ray energy 35 keV (λ= 0.0354 nm). The filter has 0.6 mm thickness in the Bragg case or 1.075 mm or 2.15 mm thickness in the Laue case. Under this condition only the refracted X-rays from object can transmit through the filter while the beam that may receive absorption and/or phase change will not. Soft tissues at human joints thus taken show high contrast images so that the DFI is promising for clinical diagnosis. Preliminary X-ray absorption images of another clinical candidates of ear bones are also shown. Its goal is its application to clini-cal diagnosis of organs that have been invisible by the ordinary techniques. In order to clinically visualize tissues in detail one needs high contrast and high spatial resolution say ~ 50 μm. This X-ray optics includes a Bragg asymmet- ric monochro-collimator and a Bragg case or a Laue case filter with capability of analyzing an angle of convergence in a parallel posi- tion. Their diffraction index is 4,4,0 and the X-ray energy 35 keV (λ = 0.0354 nm). The filter has 0.6 mm thickness in the Bragg case or 1.075 mm or 2.15 mm thickness in the Laue case. Under this condition only the refracted X-rays from object can transmit through the filter while the beam that may receive absorption and / or phase change will not. Soft tissues at human joints which taken show high contrast images so that the the DFI is promising for clinical diagnosis. Prelimi nary X-ray absorption images of another clinical candidates of ear bones are also shown.