In 1854, Katsu Rintarō was promoted to a foreign affairs position with the responsibility of translating Dutch texts, specifically tasked with translating foreign books (Western literature).
In 1855, Katsu Rintarō joined the coastal defense inspection team to investigate the defense system from Ise to Osaka Bay.
That same year, he entered the Nagasaki Naval Training Institute to study navigation and was appointed as the head naval trainee, a role similar to the general commander at a naval academy.
Due to his proficiency in Dutch, he also served as a liaison, responsible for communication between naval students and Dutch instructors.
After five years of deep studies at the Nagasaki Naval Training Institute, he graduated and returned to Edo, where he was appointed as the director of the teachers' department at the Naval Training Office, akin to the head of the faculty at the naval officer school.
