X-ray topographic study on grown-in microdefects in silicon crystals has been performed. In order to obtain a sharp and high-contrast image of the microdefects, the section topography in the Bragg-case was used and compared with that in the Laue-case. Short wave length synchrotron radiation (0.2A) was used in order to satisfy a condition that the penetration depth of the x-rays was much larger than the extinction distance. Grown-in microdefects in a slowly pulled Czochralski(CZ) grown silicon crystal and in an in situ annealed CZ-Si crystal were investigated. The microdefect images in the section topographs of the Bragg-case were clearer than in those of the Laue-case. This was explained from the fact that, in the Laue-case, defect images overlap with x-ray beams diffracted from nearly perfect regions in the crystal (the Pendellosung fringes), however, they were recorded separately on a photographic plate in the Bragg-case. Besides the strong black contrast of the microdefect images (kinematical images), dynamical diffraction images, x-ray intensity oscillations in tail parts of the defect images, were also observed. The intensity distributions of the dynamical diffraction images of the defects were compared with the dynamical theory of the x-ray diffraction in the perfect crystal in the Bragg-Laue case of type II, and qualitative agreement was obtained.