 In the five sake-producing districts in Nada, water from the river that flows from Mount Rokkō into the sea is used to power rice-polishing water mills, thus producing highly polished grains of rice, which is not possible with manpower alone.Furthermore, the combination of the cold winds, known as 'Rokko oroshi', and the influence of the inland sea makes for ideal weather conditions for brewing sake in winter.The Yamaguchi-gumi, the largest Yakuza group in Japan, and one of the largest criminal organizations in the world, has its headquarters in Nada-ku.