 The early 20th century was marked by rapid growth of industry.Entrepreneurs built factories along reclaimed land to the north of the city toward Kawasaki, which eventually grew to be the Keihin Industrial Area.The growth of Japanese industry brought affluence, and many wealthy trading families constructed sprawling residences there, while the rapid influx of population from Japan and Korea also led to the formation of Kojiki-Yato, then the largest slum in Japan.