[5] While visiting Kumamoto, the samurai Miyabe Teizō [ja] strongly encouraged Kusaka to study under Yoshida Shōin,[6] as had a friend of his brother's for some time.

[7] In his letter to Shōin, Kusaka commented: "As at the time of the Battle of Kōan the foreign envoys should be cut down, in which case the Americans will surely attack.

"[a][8] Shōin returned the letter with a note of condemnation in the margin reading: "Your argument is frivolous and its judgement shallow; it does not come from sincerity.

To employ dead old ways to solve problems in a completely changed modern world demonstrates shallow judgement.

"[b][9] In 20 August 1864 during the Kinmon incident outside the Kyoto Imperial Palace, he was wounded by a rifle fire, and committed suicide to avoid capture by ritual seppuku.