「美濃の蝮」として恐れられた斎藤道三は、その冷酷な戦術で有名だった。 1547年の加納口の戦いで織田信秀（1510ー1551）を敗北させたことで、彼は全国的に認知された。戦いの後、道三は娘濃姫（1533～35ー1612）を信秀の息子織田信長（1534ー 1582）に嫁がせ、和平協定をなした。
1556年ごろ、道三は、誰が彼の後継者になるかの憶測に囲まれているのに気づいた。噂では、道三の長子の斎藤義龍（1527-1561）は彼の本当の息子ではないと言われ、他の人々は、道三は後継者に彼より才能のある義理の息子、織田信長を考えていると話した。 斎藤義龍は自分の出生と道三の思惑に疑問を感じ、正しい相続人としての地位を確保する決心した義龍は、1556年の長良川の戦いで、父親を襲撃した。
義龍は斎藤氏の大多数を自分の力で結集させ、62歳の父親道三を一方的な戦いで敗北させ殺害した。信長は義父を助けるために増援を派遣したが、戦いがすでに終わった後に到着した。斎藤道三の頭部は戦闘中に奪われ、岐阜城の北にある崇福寺の近くにある道三塚に埋葬された。
Known as the “Viper of Mino,” Saito Dosan was renowned for his ruthless tactics. His defeat of Oda Nobuhide (1510–1551) at the Battle of Kanoguchi in 1547 brought him national recognition. After the battle, Dosan’s daughter, Nohime (1533~35–1612), and Nobuhide’s son Oda Nobunaga (1534–1582) were married as part of the peace treaty negotiations.
By 1556, Dosan found himself surrounded by speculation concerning who would be made his heir. Some rumors claimed that his firstborn, Saito Yoshitatsu (1527–1561), was not his natural son; others suggested that Dosan was considering his more talented son-in-law, Oda Nobunaga as his heir. Aware of the doubts about his paternity and determined to secure his position as rightful heir, Yoshitatsu killed his two siblings and attacked his father at the Battle of Nagaragawa in 1556.
Yoshitatsu was able to rally the majority of the Saito clan samurai to himself and defeated his 62-year-old father in a one-sided battle. Nobunaga sent reinforcements to aid his father-in-law, but they arrived after the battle had already ended. Dosan’s head, taken during battle, was interred in the Dosanzuka head mound near Sofukuji temple north of Gifu Castle.
