The Battle of Nagashino took place in 1575 near Nagashino Castle on the plain of Shitarabara in the Mikawa Province of Japan. Takeda Katsuyori attacked the castle when Okudaira Sadamasa rejoined the Tokugawa, and when his original plot with Oga Yashiro for taking Okazaki Castle, the capital of Mikawa, was discovered.