In 1582, after Oda Nobutada, the son of Nobunaga defeated Takato Castle, Takeda Katsuyori and his samurai with their family decided to escape Iwadono Castle. Iwadono Castle was located the east end of Kai (Yamanashi) and right next to Sagami. Because Hojo, Daimyo of Sagami, was also Katsuyori's brother in law, Katsuyori was plane to reorganize his army at the castle with the help of Hojo.

However, in March 9, Oyamada, the castle lord of Iwadono and samurai of Katsuyori, betrayed him and block the way to Sagami. Katsuyori was tapped here in Mt.Tenmoku and the only way to get out was covered by 4,000 army forces of Oda Nobutada.

Before the last battle between Nobutada and Katsuyori happened, Katsuyori let his son, Nobukatsu, Genpuku with the armer of Takeda (Tatenashi) and succeeded the lord of Takeda so that he can join the last battle as the last master of Takeda clan. After the Genpuku of Nobukatsu, Katsuyori moved Tatenashi to outside of Mt.Tenmoku.

At the Toriibata battle spot, his loyal samurai, Tsuchiya Masatsune, Komiyama Tomoharu, fought for Katsuyori. However, about 50 armies against 4000 armies would not last long, and Katsuyori and Nobukatsu did Seppuku.

When Tokugawa Ieyasu moved Kai, he built Keitokuin Temple at his last spot to dedicated him and Takeda clan.