, also known as Saità  Toshimasa (æÂÂè¤ å©æ¿), was a Japanese samurai lord and daimyo during the Sengoku period. He was also known as the for his ruthless tactics. He was appointed Governor of Yamashiro by the Imperial Court. After entering monkhood in his later years, he was also called Saità  Yamashiro-nyudà Â-no-kami (æÂÂè¤山åÂÂå ¥éÂÂå®Â).
He has historical reputation as one of , a nickname which he shared with Matsunaga Hisahide and Ukita Naoie, due to their ambitious and treasonous personality, along with the habit of resorting to underhanded tactics and assassinations to eliminate their opposition.
Saità  Dà Âsan has long been regarded as a symbolic figure of "Gekokujà Â" (the rise of those of lower status to positions of power), rising from a humble oil merchant to the ruler of Mino Province. However, recent research suggests that it was actually Dà Âsan's father who was the oil merchant. This implies that Dà Âsan's "Gekokujà Â" was a two-generation achievement involving both father and son.
He became a daimyo through Gekokujà  of Toki Yorinari at Mino Province in 1542. Yorinari was forced out of Mino by Saità  Dà Âsan.
The Saito fortress was located at Inabayama castle. He married Omi no kata, a sister of Akechi Mitsutsuna (Akechi Mitsuhide's father).
He defeated Oda Nobuhide at the Battle of Kanà Âguchi in 1547.
In 1549 Oda Nobuhide was defeated by DÃ Âsan. Nobuhide made peace with DÃ Âsan by arranging a political marriage between his son and heir, Oda Nobunaga, and DÃ Âsan's daughter, NÃ Âhime. DÃ Âsan, therefore, became the father-in-law of Oda Nobunaga. DÃ Âsan supported the marriage which allowed Nobuhide to focus on facing Imagawa Yoshimoto.
Several years later, rumors had started to circulate that Dà Âsan's firstborn son, Saità  Yoshitatsu, was not his natural son and Dà Âsan started to consider another son, Saità  Kiheiji, or even his son-in-law Oda Nobunaga, as his heirs. This caused Yoshitatsu to rebel and kill his two younger brothers. In 1556, the forces of Dà Âsan and Yoshitatsu clashed in the Battle of Nagara-gawa which resulted in the death of Dà Âsan.
Dà Âsan's head was taken by a man called Komaki Genta, a retainer of Yoshitatsu's son Saità  Tatsuoki. His remains were originally interred in Sà Âfuku-ji, but they were later moved to Jà Âzai-ji because the Nagara River kept overflowing and covering his burial mound. Both temples are located in the city of Gifu which celebrates Dà Âsan with an annual festival.
Saità  Dà Âsan is known for having a large number of pseudonyms and for frequently changing his name. Some believe that this is because there were two Saità Âs Dà Âsan, father and son, and the son adopted his father's name after his death. Other names of Saità  Dà Âsan are Minemaru (峰丸), Hà Ârenbà  (æ³Âè®åÂÂ), Matsunami Shogorà  (æ¾浪åºÂäºÂéÂÂ), Nishimura Kankurà  Masatoshi (西æÂÂÃ¥ÂÂä¹ÂéÂÂæ£å©), Shinkurà  (æ°ä¹ÂéÂÂ), Nagai Norihide (éÂኼÂè¦Âç§Â), and Saità  Sakondayu Toshimasa (æÂÂè¤左è¿Â大夫å©æ¿). The name Saità  was adopted from the former shugodai of Mino who had been overcome by the Nagai clan in the 1520s.