The increase of white immature kernel decrease the percentage of whole grain and lower the inspection grade. In the percentage of white immature kernel, especially in those of milky white rice kernel and in immature base rice kernel, varietal differences were found. Moreover number of white immature kernel were increased by decreasing quantity of photosynthesis treated with defoliation of flag leaf, additional nitrogen topdressing and increasing number of rough rice by it, decreasing the synchrony of heading with sparse planting and with early abnormal heading induced by high temperature in rearing seedling house, and delay in harvesting time. Lodging increased number of green and white immature kernel. In the case of good initial growth, deep-flood irrigation from initial growth increased kernel weight and grain yield, and heightened grain quality by suppressing large numbers of tiller. Shortage of soil moisture during grain filling period lowered grain quality by increasing white-belly rice, and decreased grain yield by reducing kernel weight. Number of these white immature kernels were decreased by increasing the amount of non-structural carbohydrates (NSC) translocated from rice shoot to rough rice(per rough rice) during the period from heading to 10 days after full heading time and by increasing the amount of NSC (per rough rice) that is subtracting grain yield of crude brown rice from its translocated NSC. In order to decrease the number of white immature kernels, the amount of fertilizer application, planting density, temperature in rearing seedling house, time of transplanting, soil moisture during grain filling period and time of harvesting are needed to be in proper, and increasing initial growth are necessary. the large numbers of tiller is controlled by deep-flood irrigation from initial growth. Addition to those cultivation method, using color-sorting machine at rice terminal since the last half of 1990 s, first-class rice was able to be processed, the percentage of first-class rice in Hokkaido was over that of all Japan.