When Masamune DATE went on an expedition against Osaki (a siege of Osaki), Yoshinao was forced to engage in a bitter struggle; however, he barely kept the family in existence thanks to Haruuji KUROKAWA, a branch family of the Mogami clan, who switched to the Osaki side.
伊達政宗が大崎征伐に乗り出すと苦戦を強いられたが、最上氏庶流の黒川晴氏が大崎方に寝返ったことで家の命脈だけは保つことができた。