Saitō Dōsan, also known as Saitō Toshimasa, was a Japanese samurai during the Sengoku period.He was also known as the Viper of Mino for his ruthless tactics. His honorific title from the Imperial Court was Yamashirō-no-kami and since he was a monk he was also called Saitō Yamashirō-nyudō-no-kami.