Identifying Yoshikiyo as the greater threat, he decided to concentrate his initial efforts on the weaker Ogasawara, and in 1550 he seized their principal castle at Fukashi, in modern Matsumoto, forcing their daimyo Ogasawara Nagatoki to flee and seek sanctuary with his ally Murakami Yoshikiyo at Katsurao.

In the end Murakami resistance melted away, and uncle and nephew succeeded in reducing Katsurao after just seven days of fighting.

[1] The fall of Katsurao broke the back of Murakami resistance to the Takeda, and most of the clan's followers subsequently went over to Shingen, while its leadership scrambled to escape Shinano Province.

According to legend, in the aftermath of the siege Yoshikyo's wife found herself caught up in a stream of refugees attempting to get across the Chikuma River, and struggled to find a place on one of the ferries as the boatmen did not recognise her.

The fall of the Murakami convinced Kenshin that he would have to intervene in Shinano to prevent Shingen seizing control of the entire province, and his resulting invasions led to the famous Battles of Kawanakajima.