was a regional ruler of Japan's Azuchi–Momoyama period through early Edo period. Heir to a long line of powerful daimyō in the Tōhoku region, he went on to found the modern-day city of Sendai. An outstanding tactician, he was made all the more iconic for his missing eye, as Masamune was often called dokuganryū (独眼竜), or the "One-Eyed Dragon of Ōshu". As a legendary warrior and leader, Masamune is a character in a number of Japanese period dramas. Early life and rise Date Masamune was born as Bontenmaru (梵天丸) later Tojiro (藤次郎) the eldest son of Date Terumune, born in Yonezawa Castle (in modern Yamagata Prefecture). At the age of 14 in 1581, Masamune led his first campaign, helping his father fight the Sōma clan. In 1584, at the age of 17, Masamune succeeded his father, Terumune, who chose to retire from his position as daimyō. Masamune's army was recognized by its black armor and golden headgear. Masamune is known for a few things that made him stand out from other daimyō of the time. In particular, his famous crescent-moon-bearing helmet won him a fearsome reputation. As a child, smallpox robbed him of sight in his right eye, though it is unclear exactly how he lost the organ entirely. Various theories behind the eye's condition exist. Some sources say he plucked out the eye himself when a senior member of the clan pointed out that an enemy could grab it in a fight. Others say that he had his trusted retainer Katakura Kojūrō gouge out the eye for him, making him the "One-Eyed Dragon" of Ōshu. The Date clan had built alliances with neighboring clans through marriages over previous generations, but local disputes remained commonplace. Shortly after Masamune's succession in 1584, a Date retainer named Ōuchi Sadatsuna defected to the Ashina clan of the Aizu region. Masamune declared war on Ōuchi and the Ashina for this betrayal, and started a campaign to hunt down Sadatsuna. Formerly amicable alliances were cast aside as he began to attack and conquer the lands of Sadatsuna's allies in pursuit, even those of his kin in Mutsu and Dewa Provinces. In the winter of 1585, one of these allies, Nihonmatsu Yoshitsugu felt defeat was approaching and chose to surrender to the Date instead. Masamune agreed to accept the surrender, but on the heavy condition that the Nihonmatsu give up most of their territory to the