Sakutarō Hagiwara was a Japanese writer of free verse, active in the Taishō and early Shōwa periods of Japan. He liberated Japanese free verse from the grip of traditional rules, and he is considered the "father of modern colloquial poetry in Japan". He published many volumes of essays, literary and cultural criticism, and aphorisms over his long career. His unique style of verse expressed his doubts about existence, and his fears, ennui, and anger through the use of dark images and unambiguous wording. He died from pneumonia aged 55.