Kazuo Wada, the former chairman of retail group Yaohan, which fell into bankruptcy in 1997, died of natural causes on Aug. 19, sources close to him said Thursday. He was 90.

At its peak, Yaohan had outlets in 16 countries spanning Asia, North and South America and Europe.

After graduating from Nippon University in 1951, Wada turned a grocery shop started by his parents in Atami, Shizuoka Prefecture, into a midsize supermarket chain.

He later sought aggressive overseas expansion — launching one of Asia's largest department stores in Shanghai in 1995 — but filed for bankruptcy protection for the core firm, Yaohan Japan Corp., in September 1997 after incurring huge debts from the collapse of the bubble economy.

The department store and supermarket group left liabilities of some ¥160 billion ($1.5 billion), which was a postwar retail record at the time.

In 2000 Wada set up a consultancy targeting young entrepreneurs in Iizuka, Fukuoka Prefecture, and focused on fostering venture companies.

His late mother Katsu is said to have been the inspiration for the 1983 hit TV drama "Oshin," which depicts a woman born in a poor farming village who overcomes challenges to succeed as a businesswoman during Japan's rapid recovery from the war.