was a Tendai monk from Mount Hiei in western Japan. He was the father of Miyabe Nagafusa and became a reputable administrator under Toyotomi Hideyoshi during the latter half of the Sengoku period of feudal Japan. His name could also be read as Miyabe Tsugimasu. Keijun received Miyabe Castle from Azai Nagamasa when he gave his support to the Azai clan. Fighting against the Oda clan during the Battle of Anegawa in 1570, Nagamasa and his counterpart Asakura Yoshikage were defeated, prompting Keijun to distrust his lord's ability, but not to the point in which he was willing to defect. In 1573, Oda Nobunaga laid siege to the Azai clan's Sawayama Castle, which was held by Isono Kazumasa. The castle fell after a siege that lasted over three months. In response, Nagamasa took Kazumasa's elderly mother, who he held hostage in Odani Castle, to the execution grounds for death. Keijun became enraged at the backstabbing qualities of Nagamasa, defected to Nobunaga and assisted him in the downfall of the Azai. As both Nagamasa and the Azai were entirely put into extinction after his defection, Keijun served under Nobunaga until the latter's death in 1582, at which time he then came to serve Toyotomi Hideyoshi, largely assisting him by means of administration and agricultural production.