The 1545 siege of Takatō castle marked the first time Takatō had been besieged. Takeda Shingen, continuing his sweep through the Ima Valley of Shinano Province, seeking to take control of the entire province, defeated Takatō Yoritsugu, the castellan. Takatō had relied on support from his allies, Ogasawara Nagatoki and Tozawa Yorichika, who failed to aid in his defense.