Carotid angiography employing a percutaneous technique, which was devised by Shimizu in 1937, was popularized among neurosurgeons in Japan soon after World War II. This opened up an opportunity for them to encounter and investigate moyamoya disease, since this disease is more common among Asians. They began to publish their findings on what is currently called moyamoya disease in the Japanese literature during the late 1950s and early 1960s. It was only in the late 1960s, however, that their studies were published in the English literature. The early history of the discovery of this disease is therefore not widely known. In 1957, Takeuchi and Shimizu reported a case of an unknown disease characterized by hypoplasia of the internal carotid arteries. In 1964, Moriyasu and his colleagues published a report of four child cases with occlusion of the internal carotid artery. They also published in the same year a report of five adult cases with occlusion of the internal carotid arteries for an unknown reason, placing special emphasis on an abnormal vascular network located at the base of the brain, which is presently termed moyamoya vessels. In 1968 and 1969, Kudo, Nishimoto, and Takeuchi, as well as Suzuki and Takaku, published their studies in the English literature, which contributed greatly to the recognition of moyamoya disease throughout the world. Takeuchi and Shimizu, and Moriyasu also deserve credit as the researchers who reported the crucial features of moyamoya disease for the first time.