And then, Choei, taken under the wing of Munenari DATE, the lord of the Uwajima Domain of Iyo Province, with the help of Keisaku NINOMIYA, one of Narutakijuku peers, was engaged in the translation of Western studies literature including strategy books as well as in the westernization of the domain's military equipment under Munenari.
その後、鳴滝塾時代の同門・二宮敬作の案内で伊予国宇和島藩主伊達宗城に庇護され、宗城の下で兵法書など蘭学書の翻訳や、宇和島藩の兵備の洋式化に従事した。