An object of the present invention is to provide a new rice cultivar that matures earlier than the original cultivar, and a method for causing a rice individual to mature earlier. The present invention relates to a rice cultivar Koshihikari kazusa no. 6 having the cultivar registration application number 25587, a progeny individual obtained by crossbreeding two individuals selected from the group consisting of an individual of the aforementioned cultivar and a progeny individual thereof, and a method for causing a rice individual to mature earlier that comprises replacing a region corresponding to a region containing base number 31,720,064 to base number 31,724,043 of the third chromosome of rice cultivar Nipponbare with a chromosome fragment composed of the corresponding region of rice cultivar Koshihikari kazusa no. 6 or rice cultivar Habataki in the third chromosome of the rice individual.
