His surname "Kumazawa" (熊沢) was changed to that of "Shigeyama" (蕃山) in 1660 and the latter, read in Sino-Japanese as "Banzan", became his posthumous courtesy title, by which even now he is commonly known.
[1] In 1634, through the introduction of Itakura Shigemasa (板倉重昌), a fudai vassal of the Tokugawa,[2] he went to serve as a page under Ikeda Mitsumasa (池田光政), the daimyo of the Okayama Domain in Bizen Province.
Banzan worked mainly in the Han school called Hanabatake Kyōjō (花畠教場), whose name means "Flowerfield Teaching Place".
This was the initial incarnation of the first school in Japan for educating commoners, Shizutani Gakkō (閑谷学校) which opened in 1670, after Banzan had left the service of his domain.
In 1654, when the Bizen plains were assailed by floods and large-scale famine, he put all his energies into assisting Mitsumasa with relief efforts.
He worked to produce fully developed strategies on agriculture, including ways of providing relief to small-scale farmers and land engineering projects to manage mountains and rivers.
In addition, while Banzan was a follower of Yōmeigaku, the official philosophy of the Edo shogunate was a different form of Neo-Confucianism, Shushigaku (朱子学).
In fact, Banzan was the first in a series of notable neo-Confucianists who would find themselves confronting the evolving critical powers of the Hayashi clan of scholars.
In 1669, on orders from the shogunate, he was put under the control of Matsudaira Nobuyuki (松平信之), the head of the Akashi Domain (明石藩), Harima Province.
Outside the realm of politics, Banzan would in time become something of a cultural hero because, while attending to actions and words which demonstrated an enduring concern for commoners and the poor.
[5] In 1910, the Meiji government honoured Banzan with the title of Upper Fourth Rank (正四位), in recognition of his contribution to the development of learning in the Edo period.