He is said to have been born into a doctor's family linked to Amenomori village in Omi, today's Nagahama, Shiga. Some say he was born in Kyoto. As a boy he studied medicine to follow his father, but later turned to Confucian learning.
Around this time he went to Edo and entered the school of the Confucian Kinoshita Jun'an. Fellow students included Arai Hakuseki and Muro Kyuso, and they were later praised together among the great masters of the Kinoshita school. Competing with fine classmates, Hoshu honed his learning.
On his teacher Jun'an's recommendation he entered the service of Tsushima domain, which handled diplomacy and trade with Korea. Tsushima mediated between the Edo shogunate and the Joseon court and needed learned men. Here Hoshu's lifework began.
Around this time he went to Nagasaki and studied spoken Chinese, believing that diplomacy required speaking directly in the other side's language, not only reading books. He is said to have later mastered both Chinese and Korean.
Moving to Tsushima, he was appointed assistant in the office of Korean affairs. He worked on state letters and diplomatic documents and on arranging ceremonies. In practice he learned the importance of knowing each side's customs and ways of thinking.
He stayed at the Waegwan, the Japanese settlement in Busan, Korea, and studied Korean in earnest. He is also said to have later helped compile the Korean primer Kyorin suchi. His attitude of learning the other side's language was rare at the time.
He escorted the Korean embassy to Edo. At this time his fellow student Arai Hakuseki pushed changes in protocol, such as styling the shogun King of Japan, and Hoshu opposed him in heated debate. The event brought out the differences between two old schoolmates.
He also escorted the Korean embassy celebrating the 8th shogun Yoshimune. Shin Yu-han, a member of the mission, wrote of Hoshu in his travel record Haeyurok. Hoshu's devotion in language and courtesy left a strong impression on the Korean side as well.
He promoted a school in Tsushima to train Korean interpreters and taught young people the language. Believing interpreters must know not only words but the other country's history and customs, he devoted himself to training people.
He wrote Kyorin teisei, summing up the principles of diplomacy with Korea. He taught that what mattered was sincere and trustful relations, neither deceiving nor quarreling but dealing with true heart. The idea is still often cited in discussing Japan-Korea exchange.
In later years he devoted himself to learning and waka in Tsushima, and is said to have resolved in old age to compose ten thousand poems. He died in Tsushima. Having practiced all his life facing a neighbor country with language and heart, Hoshu is valued as an internationalist of the Edo period.
Ōishi Kuranosuke (Yoshio)Ichikawa Danjūrō ITokugawa IenobuOgyū SoraiŌoka TadasukeTokugawa YoshimuneIshida BaiganKamo no Mabuchi
People of the Edo period ・ People by period
Based on facts found in textbooks and biographies. Uncertain points are marked as such.