Asano zaibatsu (浅野財閥) was one of the major second tier zaibatsu in Japan, formed in 1887 with the support from Shibusawa Eiichi, the founder of the Shibusawa zaibatsu and "Father of Japanese capitalism". Since 1945 when all zaibatsu were disbanded, Asano zaibatsu has spun off many companies.
Well known companies include TOA Construction Corporation (東亜建設工業), which has become the main company within the former zaibatsu now acting more like a keiretsu, as well as Taiheiyo Cement, one of the largest cement companies in Japan, former by a merger of Chichibu Onoda (itself a merger of Chichibu Cement and Onoda Cement) and Nippon Cement (formerly Asano Cement).
References
Asano zaibatsu Wikipedia(Text) CC BY-SA