In 1573, Oda Nobunaga rewarded his retainer Hashiba Hideyoshi with three districts of northern Omi Province for his achievements in the conquest of Odani Castle. Using this grant, Hideyoshi built Nagahama Castle on Lake Biwa's shore, becoming a castle-holding lord for the first time under Nobunaga's campaign for national unification.

In 1573, after being granted three districts of northern Omi by Oda Nobunaga for his role in capturing Odani Castle, Hashiba Hideyoshi renamed the lakeside town of Imahama to Nagahama and built a new castle there — the starting point of his career as a castle-holding daimyo. By instituting free markets to encourage commerce in the castle town, he first tested the governing skills that would later carry him to the unification of Japan.