Okudaira Nobumasa (奥平 信昌, 1555 – April 11, 1615) was a Japanese daimyō of the Sengoku and early Edo periods. Nobumasa's family considered their origins to have been associated with Mikawa Province. The clan was descended through the Akamatsu from the Murakami-Genji.
|Native name||奥平 信昌|
|Died||11 April 1615(aged 59–60)|
When Nobumasa was born, he was called Sadamasa (奥平 貞昌). He was the son of Okudaira Sadayoshi, an influential local figure in Mikawa. The Okudaira family were originally retainers of the Tokugawa, but were forced to join Takeda Shingen. After Shingen died and Katsuyori assumed leadership of the Takeda clan, Okudaira Sadamasa walked his men out of Tsukude Castle and rejoined the Tokugawa.
Katsuyori had Sadamasa's wife and brother – hostages to the Takeda – crucified for what the Takeda construed as betrayal.
Sadamasa's decision to remove himself and his forces from the Takeda supporters became one of the antecedents of the Battle of Nagashino in 1575. Katsuyori was enraged at Sadamasa's decision to leave the Takeda forces. Nagashino Castle was attacked by Katsuyori with a force of 15,000 troops; but Sadamasa held firm, repelling the Takeda siege until forces of a Tokugawa-Oda alliance eventually arrived to support the beleaguered Okudaira. Oda Nobunaga was so impressed by the Okudaira's performance in the battle that he offered Sadamasa the honor of adopting part of his name—Nobu. After the battle was won, the hardy warrior was changed from Sadamasa to Nobumasa.
In 1590, Nobumasa was given a fief in Miyazaki, Kōzuke. Nobumasa served as the first Kyoto shoshidai of the Edo period. When Nobumasa completed his service as Kyoto shoshidai in 1601, he was transferred to Kanō Domain in Mino Province. He built Kanō Castle in Gifu, Gifu Prefecture, and commissioned the building of Kanō Tenman-gū.
The name ("Daihannya") refers to the Daihannya sutra, made by Junkei Nagamitsu. The sword is in the possession of Oda Nobunaga who gave it to Tokugawa Ieyasu at the Battle of Anegawa, who then gave it to Okudaira Sadamasa at the Battle of Nagashino. The value of the sword during the Muromachi period, 600 kan, was associated with the sutra's 600 volumes; said to have belonged to the Ashikaga clan.
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