It was this castle that the Sanada defended twice from the Tokugawa, first in 1583 and again in 1600, putting up a very impressive defense both of those times. When Sanada Masayuki refused to hand over the Numata Castle to Tokugawa Ieyasu, it led to The Battle at Kami River. During the battle, Ieyasu charged into the Ueda Castle with a very large army. But Masayuki was ready, having an ambush party ready to attack. This effectively threw the Tokugawa army into great confusion, causing them great losses in numbers.