The Gohyakumangoku variety of sake rice from Niigata was registered in 1957, translating to "five million koku", or approximately nine million liters, in commemoration of Niigata's yield surpassing the five million koku mark that year. This rice has large, well-concentrated shimpaku in its core, making it ideal for sake brewing. The starch contained in the center allows for the effective removal of outer layers of the grain which contain proteins and lipids, preventing unwanted flavors in the sake. Additionally, its high starch content supplies koji with steady and continuous nourishment needed for fermentation. However, because of the shimpaku in the core, it is difficult to obtain a low seimaibuai, as grinding the grain will crack into the starch and break the grain.