Takeda Katsuyori built Shinpu Castle in order to increase the defenses of his territory under the continual threat posed by Nobunaga and Tokugawa forces in the area. The area where Shinpu Castle is located was the most central location of all their lands at the time and Katsuyori envisioned creating a new castle town such that he even ordered his retainers to move their homes here. It is ironic that his plans may have actually wekaened his overall defensive position and quickened the fateful fall of the Takeda clan.

After a suffering terrible defeat to Nobunaga forces at Suwa, Takeda Katsuyori's forces retreated back to Shinpu Castle. By this time his forces had dwindled from over 20,000 to a mere 3,000 men. On March 3, 1582 Katsuyori set fire to Shinpu Castle and fled with his remaining 300-400 men. By March 11, all of the remaining Takeda forces had been destroyed and the days of the Takeda clan came to an end.