Quotes from Takeuchi Unpei's books, and about them
Tsugaru on General History of Aomori Prefecture: “According to the 'General History of Aomori Prefecture' by Takeuchi Unpei, a man of Hirosaki, the shore at Kanita was once a source of iron sand, which was refined for use when Hirosaki Castle was built in the Keicho era. [auto-translated]”