Tadao Iwasaki

Tadao Iwasaki (born January 8, 1909 – March 30, 1990) was a Japanese businessman and former president of Mitsubishi Monsanto Chemical (now Mitsubishi Chemical).

Life and Family Background

He was born in Tokyo. His father was Masanosuke Hayashi (a diplomat and the eldest son of Dōsuke Hayashi), and he was the eldest son. His mother was Lady Yoshiko, whose father was Shunya Iwasaki, and mother was Yaho (the sixth daughter of Ōkō Rō). Lady Yoshiko was Shunya Iwasaki’s second daughter and was adopted by Oyata Koyata. Since Shunya was Koyata’s younger brother, Yoshiko became an adopted daughter of her uncle. Tadao entered the Iwasaki family as an adopted son-in-law.

Education

He graduated from Keio University and then studied abroad at Oxford University.

Family Relations and Connections

Tadao had a younger sister, and his brother-in-law was Eiji Shioda. His grandfather, Dōsuke Hayashi, was the fifth son of Taizen, and he was adopted by Tōkai Hayashi. Taizen’s eldest daughter, Tsuruko (Dōsuke’s elder sister), married Tōkai Hayashi. Taizen’s second daughter, Ki, also married Kiyosumi Misawa, and their daughters married notable scholars, politicians, and doctors.

Notably, Tadao was connected to the marriage of Hanktarō Nagaoka and Terumaki, and their child, Masao Nagaoka, became the president of Nikon, a Mitsubishi Group company.

Career and Achievements

After graduating from Keio University and studying at Oxford, he returned to Japan and entered the business world, eventually becoming president of Mitsubishi Monsanto Chemical.

During the post-war dismantling of zaibatsu, members of the Iwasaki family served as executives in Mitsubishi-affiliated companies. Tadao is known as the only case where a member of the Iwasaki family became president of a Mitsubishi company after the war.

Children and Spouse

He had two daughters with Yoshiko. His eldest daughter, Hiroko (born 1947), married Masao Masabuchi, a great-grandson of Jinkichi Watanabe. His second daughter, Kazuko (born 1950), married Makoto Sugagawa.

Hiroko, the eldest daughter, was married to Masao Nagaoka, who is the nephew of the 14th Jinkichi Watanabe. After graduating from Keio University’s Faculty of Economics, Masao joined Kirin Beer and later became the head of the Iwasaki Yanosuke family after Tadao’s death.

References and Sources

Information is documented in works such as Takashi Hayakawa’s "Japan’s Upper-Class Society and Family Clans" (KADOKAWA, 1983), Sōtai Sato’s "Clan Fiefs: The Revival of the Old Aristocratic Class" (Rippū Shobō, 1987), Kazu Ichikawa’s "Family Clans - Lineage of the New Privileged Class" (Kōdansha, 1993), and "Kaikyū Society: The Genealogies of the Rejuvenated Old Nobility of Heisei" Volume 1 (Yoshikawa Kōbunkan, 1996).