Hatsume no Tsubone (初芽局) was a legendary Japanese woman from the Sengoku period. She was famous as the main character of the historical novel Sekigahara by Ryōtarō Shiba. In the novel, she was Kunoichi (female ninja) sent by Tokugawa Ieyasu to spy on his political enemy Ishida Mitsunari before the Battle of Sekigahara.