Takanobu was the eldest son of Ryûzôji Chikaie and a great-grandson of Ryûzôji Iekane. His father was killed by Baba Yorichika in 1544. He became a monk at a young age and was known as Engetsu. At around age of 18 he returned to secular life and in 1548 became the head of both main branches of the Ryûzôji house (following the death of Ryûzôji Tanehide). Certain retainers had proposed that Tanehide's son, Ryûzôji Ienari, be named the lord and others doubted Takanobu's ability to rule. However, Takanobu proved himself a competent commander. In 1553 he rebelled against Shô Tokinao and the following year he took Saga Castle and drove Tokinao to Chikugo Province. Takanobu pursued and killed him in 1556. Takanobu expanded his power throughout Hizen, struggling in the Sonogi Region with the Ômura and Arima. Takanobu soon came into conflict with the Ôtomo of Bungo Province and in 1570, with Nabeshima Naoshige, dealt them a major defeat at the Battle of Iyama. The Ôtomo's defeat at the Battle of Mimigawa in 1578 at the hands of the Shimazu allowed Takanobu to expand into Higo province and east of Hizen at their expense. He defeated an Ôtomo army in Chikugo Province in 1579 and attacked the lands of the Ômura around the same time, forcing the submission of the latter in 1580. A ruthless schemer, he tricked Kamachi Shigenami into coming to a sargaku party and had him murdered, thus acquiring Kamichi's powerful Yanagawa Castle (in Chikugo)in 1579. Given the Kamachi's service to Ryûzôji Ienari during the war with Baba Yorichika in 1544-45, this was seen as especially underhanded and disturbed the Ryûzôji retainer band. Takanobu came into conflict with the Shimazu over Higo Province after 1580 while gradually wearing down the Arima of Hizen's Shimabara area. In 1584 he assembled an army of as many as 20,000 men and marched against the flagging Arima Harunobu, whose own meager forces were reinforced by Shimazu Iehisa. At the Battle of Okinawadate, Shimazu swordsmen burst into Takanobu's command post and cut him down, triggering a general rout of the Ryûzôji forces. After Takanobu's death, his son Ryûzôji Masaie submitted to the Shimazu. Takanobu's nickname was the 'Bear of Hizen' (Hizen no Kuma), at least in part a reference to his habit of wearing bearskin on his armor. At the same time he is said to have heavily indulged in alcohol and by 1580 was showing signs of advanced alcoholism, including a dulling of his mental capabilities and an increasing girth. In fact, he was carried to his last battle, Okinawadate, in a palanquin, as he was physically incapable of riding. His sons included Masaie, Ryûzôji Ietane, and Ryûzôji Ienobu.