Niijima Yae or Yamamoto Yaeko (1845-1932) was a Japanese woman of the late Edo-era who lived into the 20th century. Yae was the daughter of Yamamoto Gonpachi, one of the Aizu domain's official gunnery instructors. She herself was skilled in gunnery, and took part (cut her hairs, looked like a boy and used Spencer repeating rifle) in the defense of Aizu during the Boshin War. After the war, Yaeko went to Kyoto to care for her brother Yamamoto Kakuma, who had been a prisoner of war in Satsuma custody. She remained in Kyoto, and became a Christian in the 1870s. Soon after, she married Rev. Joseph Hardy Niijima and, together with Niijima and Kakuma, played an integral role in the founding of Doshisha University.
Yaeko was also a tea master of the Urasenke tradition, with the nom de plume of Niijima Sochiku. She also served as a nurse during the Russo-Japanese War and Sino-Japanese War. Her family claimed descent from the Takeda clan's retainer Yamamoto Kansuke.