The mash grinding process is unique to the kimoto brewing method. In Japanese it is known as motosuri or yamaoroshi. Three people work on one hangiri tub and use a tool called a kaburagai to carefully grind the steamed rice and koji. The process is repeated three times for each of the eight hangiri tubs.
The semi-solid state created by grinding is also unique to the kimoto method and nurtures a unique layer of micro-organisms. The subtleties of pressure involved in the grinding may change the delicate balance in which varieties of micro-organism flourish and vanish. This in turn affects the final flavour. At Daishichi, it would be unthinkable to skip the yamaoroshi process.