He was born at Inari in Kyoto, the eldest of six children of the masterless samurai Nojiri Kazutoshi and his wife Kame. His childhood name was Sashichiro. His father was often away seeking a post, and life was hard; later Banzan would have to interrupt his studies to support the family.
As a child he was adopted by his maternal grandfather Kumazawa Morihisa and took the Kumazawa surname. His grandfather had a house at Kirihara in Omi, where Banzan later took refuge when he was without a post. His mother's family was his support in life.
Through Kyogoku Takahiro, lord of Miyazu in Tango, he became a page to Ikeda Mitsumasa, lord of Okayama. Mitsumasa was known as a wise lord who loved learning, and this meeting later led Banzan to take a deep part in governing the domain.
When the Shimabara Rebellion broke out, Banzan asked to join the campaign but was refused. He then left the Ikeda for a time and returned to his grandfather's house in Omi. Denied the warrior's path of winning glory in battle, he began to seek a path in learning.
He entered the school of the Yomei scholar Nakae Toju, who had returned to Ogawa village in Omi. Needing to support his family, he studied with Toju only about eight months, but kept learning from him by letter. Toju's teaching, which stressed a right heart and practice, shaped Banzan's life.
Again through the Kyogoku, he returned to serve Okayama. Mitsumasa, interested in Yomei learning, valued Banzan as Toju's pupil and two years later made him an attendant with 300 koku. The young scholar had found a chance to put learning into practice in government.
He rose to captain of the musket corps, a senior samurai with 3,000 koku, and published his first work, the Yamato Seimei, this year. The next year he drafted the rules of the Hanazonokai study group for retainers, a forerunner of the domain school. His unusual rise also caused friction with the elders.
A great flood struck the Bizen plain and brought severe famine. Banzan helped Mitsumasa relieve the starving and pushed works to plant mountains with trees and control rivers to reduce disasters. He later taught that managing mountains and rivers was the basis of governing a country.
Citing an injury to his right arm and leg suffered while hunting, he resigned and left Okayama castle town for Teraguchi village in his fief. Around this time he began to call himself Banzan. His conflicts with the elders and the shogunate's wariness of Yomei learning are thought to lie behind it.
He had moved to Kyoto, mixing closely with court nobles and studying the Tale of Genji and court music, but the Kyoto deputy, wary of his ties to the court, drove him out, and he fled to Mount Yoshino. Two years later he was placed under Matsudaira Nobuyuki of Akashi at Taisanji and devoted himself to writing.
He published the Shugi Washo, setting out his views on learning and government in question-and-answer form. It stressed that warriors and farmers alike must be able to make a living and taught the importance of managing mountains and rivers. It also held that the shogun, though ruling the realm, remained the emperor's subject.
He had moved to Koga at the invitation of its lord Matsudaira Tadayuki, but his Daigaku Wakumon, setting out political proposals, was judged a criticism of the shogunate and he was ordered into confinement. Thanks to the lord's consideration, it is said, he still walked the domain and guided projects such as building reservoirs.
That year he died of illness in Koga, and Lord Tadayuki buried him with Confucian rites. His thought drew renewed attention at the end of the Edo period, influencing Fujita Toko and Yoshida Shoin, and Katsu Kaishu called him a hero in Confucian robes.
Fujita TokoKatsu KaishūYoshida ShōinNakae Tōju
Nakae TōjuHoshina MasayukiNonaka KenzanKawamura ZuikenAmakusa ShirōMitsui TakatoshiYamaga SokoSakai Tadakiyo
People of the Edo period ・ People by period
Based on facts found in textbooks and biographies. Uncertain points are marked as such.