오슈 후지와라 씨
The area around Hirosaki formed part of the domains of the Northern Fujiwara in the Heian period; Minamoto no Yoritomo awarded it to the Nanbu clan in the early Kamakura period after the defeat of the Northern Fujiwara (1189). During the Sengoku period a local retainer of the Nambu, Ōura Tamenobu, declared his independence (1571) and seized local castles. He pledged fealty to Toyotomi Hideyoshi at the Battle of Odawara in 1590, and was confirmed in his holdings with revenues of 45,000 "koku". He also changed his name to "Tsugaru". After siding with Tokugawa Ieyasu at the Battle of Sekigahara, he was re-confirmed in his holdings with a nominal "kokudaka" of 47,000 "koku" and he began construction of a castle in Takaoka (present-day Hirosaki). This marked the start of Hirosaki Domain under the Tokugawa shogunate. His successor, Tsugaru Nobuhira, completed the castle in 1611, but its massive 5-story "tenshu" was lost to lightning in 1627. The domain's "kokudaka" increased to 100,000 "koku" in 1628.