Kanji: 斎藤 道三
Other Known Names: Saitō Dōsan Toshimasa, the Viper of Mino
Saitō clan mon
Saitō Dōsan was the daimyo of Mino, the father of Nōhime, and the father-in-law to Oda Nobunaga. He was an oil seller and priest before he became a daimyo and fought mainly against Oda Nobuhide until the arranged marriage of their children in 1549. Little is known about his life. The traditional story states that he was born in Yamashiro Province and was the illegitimate son of Matsuda Motomune. He attempted to start a career as an oil seller and took the name of Nishimura Kankurō. Not long after, he entered the service of Nagai Nagahiro, a servant of the Toki clan of Mino Province.
There is another version of his past, stating that he was the son of Shinzaemonjō, a monk at the Myoukskuji Temple in Kyōto, who left the priesthood to marry the daughter of an oil merchant. His father became an oil merchant and later served the Nagai clan.
Regardless of origin, Saitō Dōsan caused a lot of instability within Mino. In 1562, Toki Yoshinari gave Dōsan his own concubine just to appease him. He succeeded his father in 1533, and he overthrew the Nagai in 1542, taking control of the Mt. Kinka area. By 1544, he had overthrown the Toki clan and became the daimyo of Mino and ordered the construction of Inabayama Castle. He was known for being a ruthless schemer and he murdered many of his superiors to his rise to the top.
He defeated Oda Nobuhide at the Battle of Kanoguchi and the following year, peace between the two clans was made with the marriage of Nōhime and Nobunaga. It was not long after the peace made with the Oda clan, Dōsan began to decide who would be the successor to his clan. Normally, that would follow to the eldest son, however, Dōsan’s eldest son, Yoshitatsu, had questionable lineage. It was unclear if he was Dōsan’s real son. Dōsan was considering one of his other sons to become his heir, however, Yoshitatsu killed two of his brothers after he learned of the news. He went to war against his father in 1556. Saitō Dōsan would lose this war, for he was killed and beheaded at the Battle of Nagaragawa.