At the recommendation of Naomasa NABESHIMA, the lord of domain, NAKAMUTA entered a naval school in Nagasaki at the age of 20 in 1856, and after graduation, he served as an assistant of mayor in the domain's Navy and contributed to its development.
藩主・鍋島直正の推薦で安政3年(1856年)、20歳で長崎海軍伝習所へ入所し、卒業後には佐賀藩海軍方助役を務めて海軍力の発展を促す。