Yoshida Shōin
Takasugi joined the "Shōka Sonjuku", the famous private school of Yoshida Shōin. Takasugi devoted himself to the modernization of Chōshū's military, and became a favorite student of Yoshida. In 1858, he entered the "Shōheikō" (a military school under direct control of the "shōgun" at Edo). When his teacher was arrested during the Ansei Purge in 1859, Takasugi visited him in jail. Shōin was later executed in 21 November 1859. In December 1859 he returned home by the clan's command.