The study looked at how nitrogen levels and planting density affect the quality of japonica rice grains. They used two types of rice and found that one had more chalky grains than the other. Increasing nitrogen or decreasing planting density raised protein levels but lowered taste value. The amylose content varied between the two types of rice. Lower nitrogen and higher planting density improved the quality of both types of rice, but breeding methods are needed to improve certain grain characteristics.