Empress Kōgyoku, also known as Empress Saimei, was the 33rd ruler of Japan, reigning from 642 to 645 AD. She was the first woman to hold the title of empress in her own right, following her brother, Emperor Jomei. Her reign was marked by efforts to strengthen the central government and promote Buddhism. Kōgyoku's rule faced challenges, including political intrigue and power struggles. In 645, she abdicated the throne in favor of her son, Prince Naka no Ōe, who later became Emperor Tenji. Her legacy includes contributions to the development of the Japanese imperial system and the promotion of cultural advancements.