Sano Shimenosuke joined the Shinsengumi with Itô Kashitarô. When Itô formed the Goryô Eji, he stayed in the Shinsengumi as a spy. But he protested to become a Bakufu retainer because it againt his Sonnô ideology. He tried to join the Goryô Eji but was refused by Itô. Then he asked Aizu han for permission to leave the Shinsengumi but was also refused. He and other 3 members Ibaraki Tsukasa, Nakamura Gorô, Tomikawa Jurô lost the way out and commited Seppuku.
His gravesite confirms this, stating that he committed suicide on 6/14/1867, however other sources state that he was actually killed by Ôishi Kuwajirô and others.
- Shinsengumi - Honor and Determination of the Mibu Rôshi (血誠新撰組-峻烈壬生浪士忠と斬), Rekishi Gunzô series #31, Gakken, Japan, 2003
- Shinsengumi Zentaishi Tettei Guide (新選組全隊士徹底ガイド) Maeda Masaki
- J-Wikipedia Sano Shimenosuke