The increase of white immature kernel decrease the percentage of whole grain and lower the inspection grade. In the occurrence rate of white immature kernel, especially in those of milky white rice kernel and in immature base rice kernel, differences among varieties were found. Number of white immature kernel were increased by decreasing quantity of photosynthesis treated with defoliation of flag leaf. Poor panicle uniformity results from abnormal heading in early stage caused by high temperature in sparse planting and seedling raising, and delay in harvesting time etc., All of this will cause the increase of white immature grains. In addition, lodging will lead to the increase of green and white immature grains. Under the condition of good growth at the initial stage, deep water irrigation from tillering stage inhibited the production of excess tillers, increased grain weight and brown rice yield, and improved the quality of brown rice. Because the soil in mature stage is too dry, the decrease of quality and 1000 grain weight caused by the production of abdominal white grains will lead to the decrease of yield. 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 improved cultivation method, using color-sorting machine in the common drying and storage facilities after the mid-1990 s, the proportion of first-class rice in Hokkaido exceeded the national average level in Japan.