Original diary written by Michinaga and an early transcription of it produced in the second half of the 11th century. Michinaga was the most influential person in the Japanese imperial court from the late 10th to the early 11th century. He achieved great wealth and prosperity with his political and economic power. It is the world's oldest autographic diary and a personal record of a historically important person. It includes vivid depictions of political, economic, social, cultural, religious and international events and matters at the centre of power during a time in the Heian period (794-1192) when Japan's court culture reached its peak, making it an extremely significant document for both Japanese and world history.