Saitō Dōsan

Saitō Dōsan
斎藤道三
Head of Saitō clan
In office
1542–1556
Succeeded bySaitō Yoshitatsu
Lord of Mino
In office
1542–1556
Preceded byToki Yorinari
Succeeded bySaito Yoshitatsu
Personal details
Born1494
DiedMay 28, 1556(1556-05-28) (aged 61–62)
RelationsOda Nobunaga (son in law)
Akechi Mitsutsuna (brother in law)
ChildrenSaitō Yoshitatsu
Nōhime
Nickname"Viper of Mino"
Military service
Allegiance Toki clan
Saitō clan
RankDaimyo
Unit Saitō clan
CommandsInabayama Castle
Battles/warsMino Campaign (1542)
Battle of Kanōguchi (1547)
Battle of Nagara-gawa (1556) 

Saitō Dōsan (斎藤 道三; 1494 – May 28, 1556), also known as Saitō Toshimasa (斎藤 利政), was a Japanese samurai lord and daimyo during the Sengoku period. He was also known as the "Viper of Mino" (美濃の蝮, Mino no Mamushi) 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 Saitō Yamashiro-nyudō-no-kami (斎藤山城入道守).

He has historical reputation as one of Japan's Three Great Villains (日本三大梟雄), 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.