Surgeon Hanaoka Seishū performed on 13 October 1804 the first documented surgical operation under general anesthesia in history: a mastectomy on Kan Aiya, a 60-year-old patient with breast cancer, in Hirayama, Kii Province. His anesthetic compound tsūsensan, developed over nearly twenty years by combining Chinese medicine with Dutch surgical techniques, used alkaloids from Datura stramonium and Aconitum japonicum — direct precursors of modern atropine and scopolamine. He went on to perform more than 150 breast surgeries. Japan's isolation policy (Sakoku) kept this achievement completely unknown to Western science, which attributed the invention of general anesthesia to Crawford Long (1842) and William Morton (1846).