This means a variety of sakamai that isn't one of the conventional varieties that existed naturally since the old times but has been artificially developed by breweries, as well as through changes in the methods of growing and distribution, in keeping with the quality of sake they aim for through their own cross-fertilization or development by educational institutions or private-sector companies.
古くから自然に存在する在来種ではなく、人工的に開発された品種のうちで、栽培・流通の形態変化の酒蔵が製成酒の目標とする酒質にあわせて自社交配したり、その他民間会社や教育機関が開発した酒米の品種をさす。