was a Japanese writer, editor and translator. His novels Geisha in Rivalry and A Strange Tale from East of the River are noted for their depictions of life of the demimonde in early 20th-century Tokyo.
Biography
right|thumb|180px|Nagai Kyūichirō, Kafū's father
Nagai was born Sōkichi Nagai () in Koishikawa, Bunkyō, Tokyo, as the eldest son of government official Kyūichirō Nagai and his wife Tsune, the daughter of scholar Washizu Kidō. His father was an elite government official in the Home Ministry, who had studied as an exchange student in the United States During his childhood, he visited a Chinese language school, and, under his mother's influence, was taught singing and playing music instruments, showing a fondness for utazawa, a late Edo era style of singing accompanied by the shamisen. From 1897 on, he started his regular visits to the Yoshiwara red-light district, accompanied by his friend and writer Seiichi Inoue. His contempt for the militarist regime, which in turn regarded his work as subversive for the war effort, led to a halt of the publishing of his writings until the end of World War II.